Hard carbon is a vital anode material for sodium-ion batteries;however,the nonuniform growth of solid electrolyte interphase(SEI)film substantially diminishes its initial coulombic efficiency(ICE)and cycle life.The ch...Hard carbon is a vital anode material for sodium-ion batteries;however,the nonuniform growth of solid electrolyte interphase(SEI)film substantially diminishes its initial coulombic efficiency(ICE)and cycle life.The chemical and morphological properties of surface highly influence the electrode/electrolyte interfacial reactions.In this study,we have tuned orbital hybridization states forming an interface enriched with sp^(2) hybridized carbon(sp^(2)-C),which decreases the binding energy to solvent molecules and inhibits excessive solvent decomposition during SEI formation.Benefiting from successfully constructed inorganic-rich SEI,the ICE increased to 91%and sodium storage capacity reached 346 mAh/g.Besides,the capacity retention rate was 90.7%after 700 cycles at 1 A/g higher than pristine electrode(83.8%).展开更多
C/SiO_(x)anode with higher capacity and lower lithiation potential has been recognized as a nextgeneration alternative to graphite for high-energy-density lithium-ion batteries.However,C/SiO_(x)suffers from low initia...C/SiO_(x)anode with higher capacity and lower lithiation potential has been recognized as a nextgeneration alternative to graphite for high-energy-density lithium-ion batteries.However,C/SiO_(x)suffers from low initial Coulombic efficiency(ICE),which significantly hinders its practical application.Herein,we reported a straightforward iodine redox chemistry strategy to realize highly reversible Li storage behavior and remarkably enhanced ICE of high-capacity C/SiO_(x)anode toward long-life lithium-ion batteries.Specifically,I2is introduced into porous C/SiO_(x)via simple fumigation to synthesize their composite(C/SiO_(x)@I),in which I_(2)can effectively inhibit the irreversible lithiation reactions of SiO_(x)through redox reaction.Further,redox reaction intermediates of LiI_(3)and LiIO_(3)can inhibit the decomposition of electrolyte and LiPF6,thereby reducing the thickness of the solid-electrolyte interphase film.Consequently,the obtained C/SiO_(x)@I exhibits a considerable capacity of 1241 mAh g^(-1)with an improved ICE of 88.5%at 0.1 A g^(-1)and impressive cyclability,showing capacity retention of 95%after 700 cycles at5.0 A g^(-1).Besides,the C/SiO_(x)@I with a 12%addition ratio can greatly enhance the capacity of graphite from 352 to 454 mAh g^(-1),with negligible impact on its ICE.When the addition ratio is 9%,the energy density of the 18,650 cylindrical battery composed of graphite and Li[Ni_(0.8)Co_(0.1)Mn_(0.1)]O_(2)can be enhanced by approximately 25 Wh kg^(-1).This study opens a new avenue for developing high ICE in SiO_(x)-based anodes for high-energy-density lithium-ion batteries.展开更多
The application of Sb_(2)S_(3)with marvelous theoretical capacity for alkali metal-ion batteries is seriously limited by its poor electrical conductivity and low initial coulombic efficiency(ICE).In this work,natural ...The application of Sb_(2)S_(3)with marvelous theoretical capacity for alkali metal-ion batteries is seriously limited by its poor electrical conductivity and low initial coulombic efficiency(ICE).In this work,natural stibnite modified by carbon dots(Sb_(2)S_(3)@xCDs)is elaborately designed with high ICE.Greatly,chemical processes of local oxidation–partial reduction–deep coupling for stibnite reduction of CDs are clearly demonstrated,confirmed with in situ high-temperature X-ray diffraction.More impressively,the ICE for lithium-ion batteries(LIBs)is enhanced to 85%,through the effect of oxygen-rich carbon matrix on C–S bonds which inhibit the conversion of sulfur to sulfite,well supported by X-ray photoelectron spectroscopy characterization of solid electrolyte interphase layers helped with density functional theory calculations.Not than less,it is found that Sb–O–C bonds existed in the interface effectively promote the electronic conductivity and expedite ion transmission by reducing the bandgap and restraining the slip of the dislocation.As a result,the optimal sample delivers a tremendous reversible capacity of 660 mAh g^(−1)in LIBs at a high current rate of 5 A g^(−1).This work provides a new methodology for enhancing the electrochemical energy storage performance of metal sulfides,especially for improving the ICE.展开更多
Initial Coulombic efficiency(ICE)has been widely adopted in battery research as a quantifiable indicator for the lifespan,energy density and rate performance of batteries.Hard carbon materials have been accepted as a ...Initial Coulombic efficiency(ICE)has been widely adopted in battery research as a quantifiable indicator for the lifespan,energy density and rate performance of batteries.Hard carbon materials have been accepted as a promising anode family for sodium-ion batteries(SIBs)owing to their outstanding performance.However,the booming application of hard carbon anodes has been significantly slowed by the low ICE,leading to a reduced energy density at the cell level.This offers a challenge to develop high ICE hard carbon anodes to meet the applications of high-performance SIBs.Here,we discuss the definition and factors of ICE and describe several typical strategies to improve the ICE of hard carbon anodes.The strategies for boosting the ICE of such anodes are also systematically categorized into several aspects including structure design,surface engineering,electrolyte optimization and pre-sodiation.The key challenges and perspectives in the development of high ICE hard carbon anodes are also outlined.展开更多
Hard carbon(HC) is considered as a commercial candidate for anode materials of sodium-ion batteries due to its low cost and excellent capacity. However, the problem of low initial Coulombic efficiency is still urgentl...Hard carbon(HC) is considered as a commercial candidate for anode materials of sodium-ion batteries due to its low cost and excellent capacity. However, the problem of low initial Coulombic efficiency is still urgently needed to be solved to promote the industrialization of HC.In this paper, 2,2-dimethylvinyl boric acid(DEBA) is used to modify the surface of HC to prepare HC-DEBA materials. During the cycling, the C = C bonds of DEBA molecules will be in situ electro-polymerized to form a polymer network, which can act as the passive protecting layer to inhibit irreversible decomposition of electrolyte,and induce a thinner solid electrolyte interface with lower interface impedance. Therefore, HC-DEBA has higher initial Coulombic efficiency and better cycling stability. In ester-based electrolyte, the initial Coulombic efficiency of the optimized HC-DEBA-3% increases from 65.2% to77.2%. After 2000 cycles at 1 A·g^(-1), the capacity retention rate is 90.92%. Moreover, it can provide a high reversible capacity of 294.7 m Ah·g^(-1) at 50 mA·g^(-1). This simple surface modification method is ingenious and versatile,which can be extended to other energy storage materials.展开更多
Sodium-ion batteries(SIBs) have gained more scientists’ interest, owing to some facts such as the natural abundance of Na, the similarities of physicochemical characteristics between Li and Na. The irreversible Na+io...Sodium-ion batteries(SIBs) have gained more scientists’ interest, owing to some facts such as the natural abundance of Na, the similarities of physicochemical characteristics between Li and Na. The irreversible Na+ions consumption during the first cycle of charge/discharge process(due to the formation of the solid electrolyte interface(SEI) on the electrode surface and other irreversible reactions) is the factor that determines high performance SIBs and largely reduces the capacity of the full cell SIBs. Thus, the initial coulombic efficiency(ICE) of SIBs for both anode and cathode materials, is a key parameter for high performance SIBs, and the point is to increase the transport rate of the Na+ions. Therefore, developing SIBs with high ICE and rate performance becomes vital to boost the commercialization of SIBs. Here we provide a review on the methods to improve the ICE and the rate performance, by summarizing some methods of improving the ICE and rate performance of the anode and cathode materials for SIBs, and end by a conclusion with some perspectives and recommendations.展开更多
Due to the abundant sodium reserves and high safety,sodium ion batteries(SIBs)are foreseen a promising future.While,hard carbon materials are very suitable for the anode of SIBs owing to their structure and cost advan...Due to the abundant sodium reserves and high safety,sodium ion batteries(SIBs)are foreseen a promising future.While,hard carbon materials are very suitable for the anode of SIBs owing to their structure and cost advantages.However,the unsatisfactory initial coulombic efficiency(ICE)is one of the crucial blemishes of hard carbon materials and the slow sodium storage kinetics also hinders their wide application.Herein,with spherical nano SiO_(2)as pore-forming agent,gelatin and polytetrafluoroethylene as carbon sources,a multi-porous carbon(MPC)material can be easily obtained via a co-pyrolysis method,by which carbonization and template removal can be achieved synchronously without the assistance of strong acids or strong bases.As a result,the MPC anode exhibited remarkable ICE of 83%and a high rate capability(208 m Ah/g at 5 A/g)when used in sodium-ion half cells.Additionally,coupling with Na3V2(PO4)3as the cathode to assemble full cells,the as-fabricated MPC//NVP full cell delivered a good rate capability(146 m Ah/g at 5 A/g)as well,implying a good application prospect the MPC anode has.展开更多
Amorphous carbon shows great potential as an anode material for high-performance potassium-ion batteries;however,its abundant defects or micropores generally capture K ions,thus resulting in high irreversible capacity...Amorphous carbon shows great potential as an anode material for high-performance potassium-ion batteries;however,its abundant defects or micropores generally capture K ions,thus resulting in high irreversible capacity with low initial Coulombic efficiency(ICE)and limited practical application.Herein,pore engineering via a facile self-etching strategy is applied to achieve mesoporous carbon(meso-C)nanowires with interconnected framework.Abundant and evenly distributed mesopores could provide short K^+ pathways for its rapid diffusion.Compared to microporous carbon with highly disordered structure,the meso-C with Zn-catalyzed short-range ordered structure enables more K^+to reversibly intercalate into the graphitic layers.Consequently,the mesoC shows an increased capacity by ~100 mAh g^-1 at 0.1 A g^-1,and the capacity retention is 70.7% after 1000 cycles at 1 A g^-1.Multiple in/ex situ characterizations reveal the reversible structural changes during the charging/discharging process.Particularly,benefiting from the mesoporous structure with reduced specific surface area by 31.5 times and less defects,the meso-C generates less irreversible capacity with high ICE up to 76.7%,one of the best reported values so far.This work provides a new perspective that mesopores engineering can effectively accelerate K^+ diffusion and enhance K^+ adsorption/intercalation storage.展开更多
Hard carbon(HC)is a promising anode material for sodium ion batteries(SIBs),whereas inferior initial coulombic efficiency(ICE)severely limits its practical application.In the present work,we propose an in situ electro...Hard carbon(HC)is a promising anode material for sodium ion batteries(SIBs),whereas inferior initial coulombic efficiency(ICE)severely limits its practical application.In the present work,we propose an in situ electrochemical presodiation approach to improve ICE by mixing sodium biphenyl(Na-Bp)dimethoxyethane(DME)solution with DME-based ether electrolyte.A solid electrolyte interface(SEI)could be formed beforehand on the HC electrode and Na^(+)was absorbed to nanopores and graphene stacks,compensating for the sodium loss and preventing electrolyte decomposition during the initial charge and discharge cycle.By this way,the ICE of half-cells was increased to nearly 100%and that of full-cells from 45%to 96%with energy density from 132.9 to 230.5 W h kg^(-1).Our work provides an efficient and facile method for improving ICE,which can potentially promote the practical application of HCbased materials.展开更多
Low initial Coulombic efficiency (ICE) is an important impediment to practical application of Li-rich layered oxides (LLOs), which is due to the irreversible oxygen release. It is generally considered that surface oxy...Low initial Coulombic efficiency (ICE) is an important impediment to practical application of Li-rich layered oxides (LLOs), which is due to the irreversible oxygen release. It is generally considered that surface oxygen vacancies are conducive to the improvement of ICE of LLOs. To reveal the relation of oxygen vacancies and ICE, sample PLO (Li-Mn-Cr-O) and its treated product (TLO) are comprehensive investigated in this work. During the treated process, part of oxygen atoms return to original constructed vacancies. It makes oxygen vacancies in sample TLO much poorer than those in sample PLO, and induces the formation of Li-poor spinel-layered integrated structure. Electrochemical measurement indicates the ICE of sample PLO is only 80.8%, while sample TLO is almost full reversible with the ICE of ~97.1%. In term of high-energy X-ray diffraction, scanning transmission electron microscopy, X-ray photoelectron spectroscopy and synchrotron hard/soft X-ray absorption spectroscopy, we discover that the ICE is difficult to be improved significantly just by building oxygen vacancies. LLOs with high ICE not only have to construct suitable oxygen vacancies, but also require other components with Li-poor structure to stabilize oxygen. This work provides deep insight into the mechanism of high ICE, and will contribute to the design and development of LLOs for next-generation high-energy lithium-ion batteries.展开更多
Silicon monoxide(SiO)has aroused increased attention as one of the most promising anodes for high-energy density Li-ion batteries.To enhance the initial Coulombic efficiencies(ICE)and cycle stability of SiO-based anod...Silicon monoxide(SiO)has aroused increased attention as one of the most promising anodes for high-energy density Li-ion batteries.To enhance the initial Coulombic efficiencies(ICE)and cycle stability of SiO-based anodes,a new facile composition and electrode design strategy have been adapted to fabricate a SiO-Sn-Co/graphite(G)anode.It achieves a unique structure where tiny milled SiO-Sn-Co particles are dispersed among two graphite layers.In this hybrid electrode,Sn-Co alloys promoted Li;extraction kinetics,and the holistic reversibility of SiO and graphite enhanced the electrical conductivity.The SiO-Sn-Co/G electrode delivered an average ICE of 77.6%and a reversible capacity of 640 mAh g^(-1)at 800 mA g^(-1),and the capacity retention was above 98%after 100 cycles,which was much higher than that of the SiO with an ICE of 55.3%and a capacity retention of 50%.These results indicated that this was reliable method to improve the reversibility and cycle ability of the SiO anode.Furthermore,based on its easy and feasible fabrication process,it may provide a suitable choice to combine other alloy anodes with the graphite anode.展开更多
Li-rich Mn-based oxides(LRMOs)hold great promise as next-generation cathode materials for high-energy Li-ion batteries because of their low cost and high capacity.Nevertheless,the practical application of LRMOs is imp...Li-rich Mn-based oxides(LRMOs)hold great promise as next-generation cathode materials for high-energy Li-ion batteries because of their low cost and high capacity.Nevertheless,the practical application of LRMOs is impeded by their low initial Coulombic efficiency and rapid voltage decay.Herein,a V-doped layered-spinel coherent layer is constructed on the surface of a Co-free LRMO through a simple treatment with NH_(4)VO_(3).The layered-spinel coherent layer with 3D ion channels enhanced Li+diffusion efficiency,mitigates surface-inter-face reactions and suppresses irreversible oxygen release.Notably,V-doping significantly reduces the Bader charge of oxygen atoms,thereby impeding excessive oxidation of oxygen ions and further enhancing the stability of O-redox.The modified LRMO exhibites a remarkable initial Coulombic efficiency of 91.6%,signifi-cantly surpassing that of the original LRMO(74.4%).Furthermore,the treated sample showes an impressive capacity retention rate of 91.9%after 200 cycles,accompanied by a voltage decay of merely 0.47 mV per cycle.The proposed treatment approach is straightforward and significantly improves the initial Coulombic efficiency,voltage stability,and capacity stability of LRMO cathode materials,thus holding considerable promise for the development of high-energy Li-ion batteries.展开更多
Silicon suboxide(SiO_(x),x≈1)is promising in serving as an anode material for lithium-ion batteries with high capacity,but it has a low initial Coulombic efficiency(ICE)due to the irreversible formation of lithium si...Silicon suboxide(SiO_(x),x≈1)is promising in serving as an anode material for lithium-ion batteries with high capacity,but it has a low initial Coulombic efficiency(ICE)due to the irreversible formation of lithium silicates during the first cycle.In this work,we modify SiO_(x) by solid-phase Mg doping reaction using low-cost Mg powder as a reducing agent.We show that Mg reduces SiO_(2) in SiO_(x) to Si and forms MgSiO_(3) or Mg_(2)SiO_(4).The MgSiO_(3) or Mg_(2)SiO_(4) are mainly distributed on the surface of SiO_(x),which suppresses the irreversible lithium-ion loss and enhances the ICE of SiO_(x).However,the formation of MgSiO_(3) or Mg_(2)SiO_(4) also sacrifices the capacity of SiO_(x).Therefore,by controlling the reaction process between Mg and SiO_(x),we can tune the phase composition,proportion,and morphology of the Mg-doped SiO_(x) and manipulate the performance.We obtain samples with a capacity of 1226 mAh g^(–1) and an ICE of 84.12%,which show significant improvement over carbon-coated SiO_(x) without Mg doping.By the synergistical modification of both Mg doping and prelithiation,the capacity of SiO_(x) is further increased to 1477 mAh g^(–1) with a minimal compromise in the ICE(83.77%).展开更多
Silicon anodes are promising for high-energy-density lithium-ion batteries.Nevertheless,unsatisfied initial Coulombic efficiency(ICE)and structure collapse are two barriers still hindering their application.Here,we re...Silicon anodes are promising for high-energy-density lithium-ion batteries.Nevertheless,unsatisfied initial Coulombic efficiency(ICE)and structure collapse are two barriers still hindering their application.Here,we report a 5 at.%-vanadium hybriding strategy to stabilize Si film anode,which delivers a high initial Coulombic efficiency of 92.1%with a discharge capacity of 2434.9 mAh·g^(−1) and a desirable capacity retention of 80%after 100 cycles at 1 A·g^(−1).Physical and electrochemical analyses demonstrate the Li_(x)PO_(y)F_(z)-rich inorganic solid-electrolyte interphase(SEI)and the low film internal strain are two advantageous factors for the desirable Li-ion storage reversibility and stability.A full battery with a LiFePO_(4) cathode delivers the energy densities of 291.9 and 194.6 Wh·kg^(−1) under power densities of 145.9 and 389.2 W·kg^(−1),respectively.This result on Si anodes may pave the way to next-generation highenergy-density lithium-ion batteries.展开更多
Silicon oxycarbide(SiOC)holds promise as a high-capacity anode material for lithium-ion batteries,but its performance has been consistently limited by a low initial Coulombic efficiency(ICE).In this work,a carboncoate...Silicon oxycarbide(SiOC)holds promise as a high-capacity anode material for lithium-ion batteries,but its performance has been consistently limited by a low initial Coulombic efficiency(ICE).In this work,a carboncoated SiOC composite(C/SiOC)was synthesized via chemical vapor deposition(CVD),exhibiting a significantly increased proportion of reversible Si-O-C units(94.7%)and a reduced surface area(3.629 m^(2)·g^(−1)).As a result,the C/SiOC anode delivered stable cycling over 800 cycles and achieved a remarkably high ICE of 86%.Notably,the C/SiOC composite also served as an effective host for lithium metal deposition,reducing the nucleation overpotential to 1.7 mV and promoting(110)-textured Li growth,thereby suppressing dendritic formation.This synergistic functionality resulted in excellent long-term stability in half cells(780 cycles at 1.0 mA·cm^(-2)),symmetric cells(10,000 h at 1.0 mA·cm^(-2)),and full cells(800 cycles at 1.0 C),highlighting the strong potential of C/SiOC for advanced lithium-based battery systems,including anode-free architectures.展开更多
Li_(3)VO_(4)has been a promising insertion anode material for Li-ion batteries,which has high theoretical capacity(up to~600 m Ah g^(-1))and safe Li insertion voltage(0.5–1 V vs.Li/Li^(+)).However,the low initial Cou...Li_(3)VO_(4)has been a promising insertion anode material for Li-ion batteries,which has high theoretical capacity(up to~600 m Ah g^(-1))and safe Li insertion voltage(0.5–1 V vs.Li/Li^(+)).However,the low initial Coulombic efficiency(ICE)has always been the bottleneck limiting its commercialisation.Here,we propose a facile pre-lithiation method to controllably elevate the ICE by the post-treatment of the prepared Li_(3)VO_(4)composite electrode based on an immersion reaction.In this process,the whole electrode was immersed in the liquid Li source,via which the ICE of the Li_(3)VO_(4)electrode can be controllably elevated from 80%to over 100%within 5 min of pre-lithiation.Rather than the traditional powder treatment for pre-lithiation,this process we proposed minimizes the impact of pre-lithiation on the battery assembly process.Moreover,we further investigated the effect of this pre-lithiation process on the functional components in the electrode.For the first time the ICE of Li_(3)VO_(4)electrode was elevated to 100%.As a result,the initial reversible capacity of LiFePO_(4)||Li_(3)VO_(4)full cell was improved from 44.0 to146.3 m Ah g-1,demonstrating the feasibility and great potential of the process.展开更多
Although hard carbon(HC)is currently considered to be the pioneering anode material for sodium-ion batteries(SIBs),its low initial Coulombic efficiency(ICE)results in excessive sodium consumption at the cathode in ful...Although hard carbon(HC)is currently considered to be the pioneering anode material for sodium-ion batteries(SIBs),its low initial Coulombic efficiency(ICE)results in excessive sodium consumption at the cathode in full cells,thereby significantly limiting its practical application in SIBs.Organic small molecule-assisted biomass co-thermal crosslinking is an effective strategy.Herein,through modulating the composition ratios among lignin,cellulose and hemicellulose in the raw bamboo,and then leveraging an organic small molecule(maleic anhydride,MA)-assisted thermal-crosslinking,the multiple structural features including carbon layer orientation,graphite-like domain size and closed pore structure can be precisely controlled in the HC product.The regulation of precursor components promotes the formation of sp^(2)hybridized structure within the carbon skeleton,leading to the generation of larger graphite-like microcrystalline domains.Meanwhile,the crosslinking induced by MA facilitates the development of closed pores during the final high-temperature carbonization.Consequently,the resulting HC material(HC-BO-MA)exhibits an impressive ICE of 93.9%coupled with a high reversible specific capacity of 324 mAh g^(−1)(at 20 mA g^(−1)).This work provides valuable insights for the rational design of high-performance biomass-derived HC anodes for SIBs.展开更多
The low initial Coulombic efficiency(ICE)of SiOx anode caused by the irreversible generation of LiySiOz and Li20 during lithiation process limits its application for high energy-density lithium-ion batteries.Herein,we...The low initial Coulombic efficiency(ICE)of SiOx anode caused by the irreversible generation of LiySiOz and Li20 during lithiation process limits its application for high energy-density lithium-ion batteries.Herein,we report a molten-salt-induced thermochemical.prelithiation strategy for regulating the electrochemically active Si/O ratio of SiOx and thus enhancing ICE through thermal treatment of pre-synthesized LiNH2-coated SiOx in molten LiCl at 700℃.Bulk SiOx micro-particle was transformed into pomegranatelike prelithiated micro-cluster composite(M-Li-SiOx)with SiOx core and outer nano-sized agglomerates consisting of Li2Si20s,SiO2,and Si.Through the analysis of the reaction intermediates,molten-UC!could initiate reactions and promote mass transfer by the continuous extraction of oxygen component from SiOx particle inner in the form of inert Li2Si20s and SiO2 nanotubes to realize the.prelithiation.The degree of prelithiation can be regulated by adjusting the coating amount of LiNH2 layer,and the resulted M-Li-SiOx displays a prominent improvement of ICE from 58.73%to 88.2%.The graphite/M-Li-SiOx(8:2)composite electrode delivers a.discharge capacity of 497.29 mAh·g^(-1) with an ICE of 91.79%.By pairing graphite/M-Li-SiOx anode and LiFeP04 cathode in a full-cell an enhancement of energy density of 37.25%is realized compared with the full-cell containing graphite/SiOx anode.Furthermore,,ex-situ X-ray photoelectron spectroscopy(XPS)/Raman/X-ray diffraction(XRD)and related electrochemical measurements reveal the SiOx core and Si of M-Li-SiOx participate in the lithiation,and pre-generated Li2Si20s with u+diffusivity and pomegranate-like.structure reduces the reaction resistance and interface impedance of the solid electrolyte interphase(SEI)film.展开更多
Carbonaceous materials for lithium(Li)/sodium(Na)-ion batteries have attracted significant attention because of their widespread availability,renewable nature,and low cost.During the past decades,although great effort...Carbonaceous materials for lithium(Li)/sodium(Na)-ion batteries have attracted significant attention because of their widespread availability,renewable nature,and low cost.During the past decades,although great efforts have been devoted to developing high-performance carbonaceous materials with high capacity,long life span,and excellent rate capability,the low initial Coulombic efficiency(ICE)of high-capacity carbonaceous materials seriously limits their practical applications.Various methods have been successfully exploited,and a revolutionary impact has been achieved through the utilization of different techniques.Different carbonaceous materials possess different ion storage mechanisms,which means that the initial capacity loss may vary.However,there has rarely been a special review about the origins of and progress in the ICE for carbonaceous materials from the angle of the crystal structure.Hence,in this review,the structural differences between and ion storage mechanisms of various carbonaceous materials are first introduced.Then,we deduce the correlative factors of low ICE and thereafter summarize the proposed strategies to address these issues.Finally,some challenges,perspectives,and future directions on the ICE of carbonaceous materials are given.This review will provide deep insights into the challenges of improving the ICE of carbonaceous anodes for high-energy Li/Na-ion batteries,which will greatly contribute to their commercialization process.展开更多
Industrially prepared artificial graphite(AG)is attractive for potassium-ion batteries(PIBs),but its rate performance is poor and the production process is energy intensive,so developing an efficient strategy to produ...Industrially prepared artificial graphite(AG)is attractive for potassium-ion batteries(PIBs),but its rate performance is poor and the production process is energy intensive,so developing an efficient strategy to produce novel graphite with low energy consumption and high performance is economically important.Herein,a nanostructured graphite composed of multi-walled carbon nanotubes(MWCNTs)and graphite shells was prepared by one-pot method through low-temperature pyrolysis of iron-based metal-organic framework(MOF)and carbon source.The high graphitization degree of nanostructured graphite makes the initial Coulombic efficiency(ICE)exceed 80%,and the three-dimensional(3D)conductive network ensures a specific capacity of 234 mAh·g^(−1)after 1000 cycles at a high current density of 500 mA·g^(−1).In addition,the typical graphite potassium storage mechanism is also demonstrated by in situ X-ray diffraction(XRD)and in situ Raman spectroscopy,and its practicality is also proved by the voltage of the full cells.This work provides a feasible way to optimize the practical production process of AG and expand its application in energy storage.展开更多
基金support from the Heilongjiang Province"Double First Class"Discipline Collaborative Innovation Project(No.LJGXCG2023-061).
文摘Hard carbon is a vital anode material for sodium-ion batteries;however,the nonuniform growth of solid electrolyte interphase(SEI)film substantially diminishes its initial coulombic efficiency(ICE)and cycle life.The chemical and morphological properties of surface highly influence the electrode/electrolyte interfacial reactions.In this study,we have tuned orbital hybridization states forming an interface enriched with sp^(2) hybridized carbon(sp^(2)-C),which decreases the binding energy to solvent molecules and inhibits excessive solvent decomposition during SEI formation.Benefiting from successfully constructed inorganic-rich SEI,the ICE increased to 91%and sodium storage capacity reached 346 mAh/g.Besides,the capacity retention rate was 90.7%after 700 cycles at 1 A/g higher than pristine electrode(83.8%).
基金financially supported by the National Natural Science Foundation of China(No.51962027,and 52262039)the Major Science and Technology Project of Inner Mongolia Autonomous Region(2021ZD0016)+3 种基金the National Key R&D Program of China(2020YFC1909105)the Fundamental Research Funds for Inner Mongolia University of Science&Technology(NO.2024QNJS071,2023QNJS052 and 2024QNJS064)the Program for Young Talents of Science and Technology in Universities of Inner Mongolia Autonomous Region(No.NJYT24002)the Central Guidance Fund for Local Scientific and Technological Development(2024ZY0012)。
文摘C/SiO_(x)anode with higher capacity and lower lithiation potential has been recognized as a nextgeneration alternative to graphite for high-energy-density lithium-ion batteries.However,C/SiO_(x)suffers from low initial Coulombic efficiency(ICE),which significantly hinders its practical application.Herein,we reported a straightforward iodine redox chemistry strategy to realize highly reversible Li storage behavior and remarkably enhanced ICE of high-capacity C/SiO_(x)anode toward long-life lithium-ion batteries.Specifically,I2is introduced into porous C/SiO_(x)via simple fumigation to synthesize their composite(C/SiO_(x)@I),in which I_(2)can effectively inhibit the irreversible lithiation reactions of SiO_(x)through redox reaction.Further,redox reaction intermediates of LiI_(3)and LiIO_(3)can inhibit the decomposition of electrolyte and LiPF6,thereby reducing the thickness of the solid-electrolyte interphase film.Consequently,the obtained C/SiO_(x)@I exhibits a considerable capacity of 1241 mAh g^(-1)with an improved ICE of 88.5%at 0.1 A g^(-1)and impressive cyclability,showing capacity retention of 95%after 700 cycles at5.0 A g^(-1).Besides,the C/SiO_(x)@I with a 12%addition ratio can greatly enhance the capacity of graphite from 352 to 454 mAh g^(-1),with negligible impact on its ICE.When the addition ratio is 9%,the energy density of the 18,650 cylindrical battery composed of graphite and Li[Ni_(0.8)Co_(0.1)Mn_(0.1)]O_(2)can be enhanced by approximately 25 Wh kg^(-1).This study opens a new avenue for developing high ICE in SiO_(x)-based anodes for high-energy-density lithium-ion batteries.
基金financially supported by the National Natural Science Foundation of China (51904342, 52074359, U21A20284)Hunan Provincial Science and Technology Plan (2020JJ3048)the Science and Technology Innovation Program of Hunan Province (2021RC3014, 2020RC4005, 2019RS1004)
文摘The application of Sb_(2)S_(3)with marvelous theoretical capacity for alkali metal-ion batteries is seriously limited by its poor electrical conductivity and low initial coulombic efficiency(ICE).In this work,natural stibnite modified by carbon dots(Sb_(2)S_(3)@xCDs)is elaborately designed with high ICE.Greatly,chemical processes of local oxidation–partial reduction–deep coupling for stibnite reduction of CDs are clearly demonstrated,confirmed with in situ high-temperature X-ray diffraction.More impressively,the ICE for lithium-ion batteries(LIBs)is enhanced to 85%,through the effect of oxygen-rich carbon matrix on C–S bonds which inhibit the conversion of sulfur to sulfite,well supported by X-ray photoelectron spectroscopy characterization of solid electrolyte interphase layers helped with density functional theory calculations.Not than less,it is found that Sb–O–C bonds existed in the interface effectively promote the electronic conductivity and expedite ion transmission by reducing the bandgap and restraining the slip of the dislocation.As a result,the optimal sample delivers a tremendous reversible capacity of 660 mAh g^(−1)in LIBs at a high current rate of 5 A g^(−1).This work provides a new methodology for enhancing the electrochemical energy storage performance of metal sulfides,especially for improving the ICE.
基金supported by the National Key R&D Program of China(2018YFE0201701 and 2018YFA0209401)the National Natural Science Foundation of China(Grant nos.22088101,U21A20329,21733003 and 21975050)+1 种基金the Science and Technology Commission of Shanghai Municipality(19JC1410700)Program of Shanghai Academic Research Leader(21XD1420800)。
文摘Initial Coulombic efficiency(ICE)has been widely adopted in battery research as a quantifiable indicator for the lifespan,energy density and rate performance of batteries.Hard carbon materials have been accepted as a promising anode family for sodium-ion batteries(SIBs)owing to their outstanding performance.However,the booming application of hard carbon anodes has been significantly slowed by the low ICE,leading to a reduced energy density at the cell level.This offers a challenge to develop high ICE hard carbon anodes to meet the applications of high-performance SIBs.Here,we discuss the definition and factors of ICE and describe several typical strategies to improve the ICE of hard carbon anodes.The strategies for boosting the ICE of such anodes are also systematically categorized into several aspects including structure design,surface engineering,electrolyte optimization and pre-sodiation.The key challenges and perspectives in the development of high ICE hard carbon anodes are also outlined.
基金the National Natural Science Foundation of China(Nos.21975026 and 22005033)Beijing Institute of Technology Research Fund Program for Young Scholars(No.XSQD-202108005)。
文摘Hard carbon(HC) is considered as a commercial candidate for anode materials of sodium-ion batteries due to its low cost and excellent capacity. However, the problem of low initial Coulombic efficiency is still urgently needed to be solved to promote the industrialization of HC.In this paper, 2,2-dimethylvinyl boric acid(DEBA) is used to modify the surface of HC to prepare HC-DEBA materials. During the cycling, the C = C bonds of DEBA molecules will be in situ electro-polymerized to form a polymer network, which can act as the passive protecting layer to inhibit irreversible decomposition of electrolyte,and induce a thinner solid electrolyte interface with lower interface impedance. Therefore, HC-DEBA has higher initial Coulombic efficiency and better cycling stability. In ester-based electrolyte, the initial Coulombic efficiency of the optimized HC-DEBA-3% increases from 65.2% to77.2%. After 2000 cycles at 1 A·g^(-1), the capacity retention rate is 90.92%. Moreover, it can provide a high reversible capacity of 294.7 m Ah·g^(-1) at 50 mA·g^(-1). This simple surface modification method is ingenious and versatile,which can be extended to other energy storage materials.
基金financially supported by National Key Research and Development Program of China (No.2019YFC1907805)National Natural Science Foundation of China (No.52004338)+1 种基金Hunan Provincial Natural Science Foundation of China (No.2020JJ5696)Guangdong Provincial Department of Natural Resources (No.2020-011)。
文摘Sodium-ion batteries(SIBs) have gained more scientists’ interest, owing to some facts such as the natural abundance of Na, the similarities of physicochemical characteristics between Li and Na. The irreversible Na+ions consumption during the first cycle of charge/discharge process(due to the formation of the solid electrolyte interface(SEI) on the electrode surface and other irreversible reactions) is the factor that determines high performance SIBs and largely reduces the capacity of the full cell SIBs. Thus, the initial coulombic efficiency(ICE) of SIBs for both anode and cathode materials, is a key parameter for high performance SIBs, and the point is to increase the transport rate of the Na+ions. Therefore, developing SIBs with high ICE and rate performance becomes vital to boost the commercialization of SIBs. Here we provide a review on the methods to improve the ICE and the rate performance, by summarizing some methods of improving the ICE and rate performance of the anode and cathode materials for SIBs, and end by a conclusion with some perspectives and recommendations.
基金financially supported by the Start-up Funding of Jinan University(No.88016105)the Discipline Construction Outstanding Young Backbone Project(No.12819023)+3 种基金the Fundamental Research Funds for the Central Universities(No.21620317)the Guangdong Basic and Applied Basic Research Foundation(Nos.2020A1515110611 and 2021A1515010362)the Guangzhou Basic and Applied Basic Research Foundation(No.202102020995)supported by the Open Fund of Guangdong Provincial Key Laboratory of Functional Supramolecular Coordination Materials and Applications(No.2020B121201005)。
文摘Due to the abundant sodium reserves and high safety,sodium ion batteries(SIBs)are foreseen a promising future.While,hard carbon materials are very suitable for the anode of SIBs owing to their structure and cost advantages.However,the unsatisfactory initial coulombic efficiency(ICE)is one of the crucial blemishes of hard carbon materials and the slow sodium storage kinetics also hinders their wide application.Herein,with spherical nano SiO_(2)as pore-forming agent,gelatin and polytetrafluoroethylene as carbon sources,a multi-porous carbon(MPC)material can be easily obtained via a co-pyrolysis method,by which carbonization and template removal can be achieved synchronously without the assistance of strong acids or strong bases.As a result,the MPC anode exhibited remarkable ICE of 83%and a high rate capability(208 m Ah/g at 5 A/g)when used in sodium-ion half cells.Additionally,coupling with Na3V2(PO4)3as the cathode to assemble full cells,the as-fabricated MPC//NVP full cell delivered a good rate capability(146 m Ah/g at 5 A/g)as well,implying a good application prospect the MPC anode has.
基金supported by the National Natural Science Foundation of China (51832004, 21805219 and 51521001)the National Key Research and Development Program of China (2016YFA0202603)+2 种基金the Programme of Introducing Talents of Discipline to Universities (B17034)the Yellow Crane Talent (Science & Technology) Program of Wuhan CityFoshan Xianhu Laboratory of the Advanced Energy Science and Technology Guangdong Laboratory (XHT2020-003)。
文摘Amorphous carbon shows great potential as an anode material for high-performance potassium-ion batteries;however,its abundant defects or micropores generally capture K ions,thus resulting in high irreversible capacity with low initial Coulombic efficiency(ICE)and limited practical application.Herein,pore engineering via a facile self-etching strategy is applied to achieve mesoporous carbon(meso-C)nanowires with interconnected framework.Abundant and evenly distributed mesopores could provide short K^+ pathways for its rapid diffusion.Compared to microporous carbon with highly disordered structure,the meso-C with Zn-catalyzed short-range ordered structure enables more K^+to reversibly intercalate into the graphitic layers.Consequently,the mesoC shows an increased capacity by ~100 mAh g^-1 at 0.1 A g^-1,and the capacity retention is 70.7% after 1000 cycles at 1 A g^-1.Multiple in/ex situ characterizations reveal the reversible structural changes during the charging/discharging process.Particularly,benefiting from the mesoporous structure with reduced specific surface area by 31.5 times and less defects,the meso-C generates less irreversible capacity with high ICE up to 76.7%,one of the best reported values so far.This work provides a new perspective that mesopores engineering can effectively accelerate K^+ diffusion and enhance K^+ adsorption/intercalation storage.
基金supported by the National Natural Science Foundation of China,China(51932011,52072411,52104285)the Natural Science Foundation of Hunan Province,China(2021JJ20060)+1 种基金the Science and Technology Innovation Program of Hunan Province,China(2021RC3001)the Fundamental Research Funds for the Central Universities,China(202044011)。
文摘Hard carbon(HC)is a promising anode material for sodium ion batteries(SIBs),whereas inferior initial coulombic efficiency(ICE)severely limits its practical application.In the present work,we propose an in situ electrochemical presodiation approach to improve ICE by mixing sodium biphenyl(Na-Bp)dimethoxyethane(DME)solution with DME-based ether electrolyte.A solid electrolyte interface(SEI)could be formed beforehand on the HC electrode and Na^(+)was absorbed to nanopores and graphene stacks,compensating for the sodium loss and preventing electrolyte decomposition during the initial charge and discharge cycle.By this way,the ICE of half-cells was increased to nearly 100%and that of full-cells from 45%to 96%with energy density from 132.9 to 230.5 W h kg^(-1).Our work provides an efficient and facile method for improving ICE,which can potentially promote the practical application of HCbased materials.
基金We thank the funding supports of the National Natural Science Foundation of China(Project Nos.51874104 and 52004070)the Key Technology and Supporting Platform of Genetic Engineering of Materials under States Key Project of Research and Development Plan of China(Project No.2016YFB0700600).The authors thank Cheng-Hao Chuang for the assistant with X-ray spectroscopy measurement.
文摘Low initial Coulombic efficiency (ICE) is an important impediment to practical application of Li-rich layered oxides (LLOs), which is due to the irreversible oxygen release. It is generally considered that surface oxygen vacancies are conducive to the improvement of ICE of LLOs. To reveal the relation of oxygen vacancies and ICE, sample PLO (Li-Mn-Cr-O) and its treated product (TLO) are comprehensive investigated in this work. During the treated process, part of oxygen atoms return to original constructed vacancies. It makes oxygen vacancies in sample TLO much poorer than those in sample PLO, and induces the formation of Li-poor spinel-layered integrated structure. Electrochemical measurement indicates the ICE of sample PLO is only 80.8%, while sample TLO is almost full reversible with the ICE of ~97.1%. In term of high-energy X-ray diffraction, scanning transmission electron microscopy, X-ray photoelectron spectroscopy and synchrotron hard/soft X-ray absorption spectroscopy, we discover that the ICE is difficult to be improved significantly just by building oxygen vacancies. LLOs with high ICE not only have to construct suitable oxygen vacancies, but also require other components with Li-poor structure to stabilize oxygen. This work provides deep insight into the mechanism of high ICE, and will contribute to the design and development of LLOs for next-generation high-energy lithium-ion batteries.
基金supported by the National Natural Science Foundation of China (No. 52071144, 51822104, 51831009, and 51621001)
文摘Silicon monoxide(SiO)has aroused increased attention as one of the most promising anodes for high-energy density Li-ion batteries.To enhance the initial Coulombic efficiencies(ICE)and cycle stability of SiO-based anodes,a new facile composition and electrode design strategy have been adapted to fabricate a SiO-Sn-Co/graphite(G)anode.It achieves a unique structure where tiny milled SiO-Sn-Co particles are dispersed among two graphite layers.In this hybrid electrode,Sn-Co alloys promoted Li;extraction kinetics,and the holistic reversibility of SiO and graphite enhanced the electrical conductivity.The SiO-Sn-Co/G electrode delivered an average ICE of 77.6%and a reversible capacity of 640 mAh g^(-1)at 800 mA g^(-1),and the capacity retention was above 98%after 100 cycles,which was much higher than that of the SiO with an ICE of 55.3%and a capacity retention of 50%.These results indicated that this was reliable method to improve the reversibility and cycle ability of the SiO anode.Furthermore,based on its easy and feasible fabrication process,it may provide a suitable choice to combine other alloy anodes with the graphite anode.
基金Natural Science Research(Department of Education)Project of Higher Education Institutions in Guangdong Province(Grant No.2018KQNCX063)Applied Basic Research Fund of Guangdong Province(Grant No.2024B1515020071)+1 种基金National Natural Science Foundation of China(Grant Nos.52371217 and 52150410411)Guangdong Provincial Science and Technology Plan Project(Grant No.2023A0505020009)。
文摘Li-rich Mn-based oxides(LRMOs)hold great promise as next-generation cathode materials for high-energy Li-ion batteries because of their low cost and high capacity.Nevertheless,the practical application of LRMOs is impeded by their low initial Coulombic efficiency and rapid voltage decay.Herein,a V-doped layered-spinel coherent layer is constructed on the surface of a Co-free LRMO through a simple treatment with NH_(4)VO_(3).The layered-spinel coherent layer with 3D ion channels enhanced Li+diffusion efficiency,mitigates surface-inter-face reactions and suppresses irreversible oxygen release.Notably,V-doping significantly reduces the Bader charge of oxygen atoms,thereby impeding excessive oxidation of oxygen ions and further enhancing the stability of O-redox.The modified LRMO exhibites a remarkable initial Coulombic efficiency of 91.6%,signifi-cantly surpassing that of the original LRMO(74.4%).Furthermore,the treated sample showes an impressive capacity retention rate of 91.9%after 200 cycles,accompanied by a voltage decay of merely 0.47 mV per cycle.The proposed treatment approach is straightforward and significantly improves the initial Coulombic efficiency,voltage stability,and capacity stability of LRMO cathode materials,thus holding considerable promise for the development of high-energy Li-ion batteries.
基金supported by the National Natural Science Foundation(52232009)the National Natural Science Foundation for Distinguished Young Scholar(52125404)+1 种基金the National Youth Talent Support Program,“131”First Level Innovative Talents Training Project in Tianjinthe Tianjin Natural Science Foundation for Distinguished Young Scholar(18JCJQJC46500).
文摘Silicon suboxide(SiO_(x),x≈1)is promising in serving as an anode material for lithium-ion batteries with high capacity,but it has a low initial Coulombic efficiency(ICE)due to the irreversible formation of lithium silicates during the first cycle.In this work,we modify SiO_(x) by solid-phase Mg doping reaction using low-cost Mg powder as a reducing agent.We show that Mg reduces SiO_(2) in SiO_(x) to Si and forms MgSiO_(3) or Mg_(2)SiO_(4).The MgSiO_(3) or Mg_(2)SiO_(4) are mainly distributed on the surface of SiO_(x),which suppresses the irreversible lithium-ion loss and enhances the ICE of SiO_(x).However,the formation of MgSiO_(3) or Mg_(2)SiO_(4) also sacrifices the capacity of SiO_(x).Therefore,by controlling the reaction process between Mg and SiO_(x),we can tune the phase composition,proportion,and morphology of the Mg-doped SiO_(x) and manipulate the performance.We obtain samples with a capacity of 1226 mAh g^(–1) and an ICE of 84.12%,which show significant improvement over carbon-coated SiO_(x) without Mg doping.By the synergistical modification of both Mg doping and prelithiation,the capacity of SiO_(x) is further increased to 1477 mAh g^(–1) with a minimal compromise in the ICE(83.77%).
基金supported by the National Natural Science Foundation of China(Nos.22469010 and U24A2063)Yunnan Province Natural Science Fund(Nos.202501AT070331 and 202301AT070151)Yunnan Xingdian Young Talent Project(No.KKXX202452039).
文摘Silicon anodes are promising for high-energy-density lithium-ion batteries.Nevertheless,unsatisfied initial Coulombic efficiency(ICE)and structure collapse are two barriers still hindering their application.Here,we report a 5 at.%-vanadium hybriding strategy to stabilize Si film anode,which delivers a high initial Coulombic efficiency of 92.1%with a discharge capacity of 2434.9 mAh·g^(−1) and a desirable capacity retention of 80%after 100 cycles at 1 A·g^(−1).Physical and electrochemical analyses demonstrate the Li_(x)PO_(y)F_(z)-rich inorganic solid-electrolyte interphase(SEI)and the low film internal strain are two advantageous factors for the desirable Li-ion storage reversibility and stability.A full battery with a LiFePO_(4) cathode delivers the energy densities of 291.9 and 194.6 Wh·kg^(−1) under power densities of 145.9 and 389.2 W·kg^(−1),respectively.This result on Si anodes may pave the way to next-generation highenergy-density lithium-ion batteries.
基金supported by the Natural Science Foundation of Hebei Province(No.B2023208035)funded by Science Research Project of Hebei Education Department(No.QN2025055)supported by Beijing Zhongkebaice Technology Service Co.,Ltd。
文摘Silicon oxycarbide(SiOC)holds promise as a high-capacity anode material for lithium-ion batteries,but its performance has been consistently limited by a low initial Coulombic efficiency(ICE).In this work,a carboncoated SiOC composite(C/SiOC)was synthesized via chemical vapor deposition(CVD),exhibiting a significantly increased proportion of reversible Si-O-C units(94.7%)and a reduced surface area(3.629 m^(2)·g^(−1)).As a result,the C/SiOC anode delivered stable cycling over 800 cycles and achieved a remarkably high ICE of 86%.Notably,the C/SiOC composite also served as an effective host for lithium metal deposition,reducing the nucleation overpotential to 1.7 mV and promoting(110)-textured Li growth,thereby suppressing dendritic formation.This synergistic functionality resulted in excellent long-term stability in half cells(780 cycles at 1.0 mA·cm^(-2)),symmetric cells(10,000 h at 1.0 mA·cm^(-2)),and full cells(800 cycles at 1.0 C),highlighting the strong potential of C/SiOC for advanced lithium-based battery systems,including anode-free architectures.
基金supported by the National Natural Science Foundation of China(52072138)the Shenzhen Science and TechnologyProgram(JCYJ2022530160816038and JCYJ20220818100418040)+1 种基金the Postdoctoral Fellowship Program of China Postdoctoral Science Foundation(GZC20230879)the China Postdoctoral Science Foundation(2023M74247)。
文摘Li_(3)VO_(4)has been a promising insertion anode material for Li-ion batteries,which has high theoretical capacity(up to~600 m Ah g^(-1))and safe Li insertion voltage(0.5–1 V vs.Li/Li^(+)).However,the low initial Coulombic efficiency(ICE)has always been the bottleneck limiting its commercialisation.Here,we propose a facile pre-lithiation method to controllably elevate the ICE by the post-treatment of the prepared Li_(3)VO_(4)composite electrode based on an immersion reaction.In this process,the whole electrode was immersed in the liquid Li source,via which the ICE of the Li_(3)VO_(4)electrode can be controllably elevated from 80%to over 100%within 5 min of pre-lithiation.Rather than the traditional powder treatment for pre-lithiation,this process we proposed minimizes the impact of pre-lithiation on the battery assembly process.Moreover,we further investigated the effect of this pre-lithiation process on the functional components in the electrode.For the first time the ICE of Li_(3)VO_(4)electrode was elevated to 100%.As a result,the initial reversible capacity of LiFePO_(4)||Li_(3)VO_(4)full cell was improved from 44.0 to146.3 m Ah g-1,demonstrating the feasibility and great potential of the process.
基金supported by the National Key R&D Program of China(2022YFB2402600)the National Natural Science Foundation of China(52203346)the Guangdong Basic and Applied Basic Research Foundation(2022B1515120019,2021A1515110168).
文摘Although hard carbon(HC)is currently considered to be the pioneering anode material for sodium-ion batteries(SIBs),its low initial Coulombic efficiency(ICE)results in excessive sodium consumption at the cathode in full cells,thereby significantly limiting its practical application in SIBs.Organic small molecule-assisted biomass co-thermal crosslinking is an effective strategy.Herein,through modulating the composition ratios among lignin,cellulose and hemicellulose in the raw bamboo,and then leveraging an organic small molecule(maleic anhydride,MA)-assisted thermal-crosslinking,the multiple structural features including carbon layer orientation,graphite-like domain size and closed pore structure can be precisely controlled in the HC product.The regulation of precursor components promotes the formation of sp^(2)hybridized structure within the carbon skeleton,leading to the generation of larger graphite-like microcrystalline domains.Meanwhile,the crosslinking induced by MA facilitates the development of closed pores during the final high-temperature carbonization.Consequently,the resulting HC material(HC-BO-MA)exhibits an impressive ICE of 93.9%coupled with a high reversible specific capacity of 324 mAh g^(−1)(at 20 mA g^(−1)).This work provides valuable insights for the rational design of high-performance biomass-derived HC anodes for SIBs.
基金support by the National Natural Science Foundation of China(Nos.21701163,21831006,21975244,21521001,and 22075268)the Natural Science Foundation of Anhui Provincial(No.1808085QB25)。
文摘The low initial Coulombic efficiency(ICE)of SiOx anode caused by the irreversible generation of LiySiOz and Li20 during lithiation process limits its application for high energy-density lithium-ion batteries.Herein,we report a molten-salt-induced thermochemical.prelithiation strategy for regulating the electrochemically active Si/O ratio of SiOx and thus enhancing ICE through thermal treatment of pre-synthesized LiNH2-coated SiOx in molten LiCl at 700℃.Bulk SiOx micro-particle was transformed into pomegranatelike prelithiated micro-cluster composite(M-Li-SiOx)with SiOx core and outer nano-sized agglomerates consisting of Li2Si20s,SiO2,and Si.Through the analysis of the reaction intermediates,molten-UC!could initiate reactions and promote mass transfer by the continuous extraction of oxygen component from SiOx particle inner in the form of inert Li2Si20s and SiO2 nanotubes to realize the.prelithiation.The degree of prelithiation can be regulated by adjusting the coating amount of LiNH2 layer,and the resulted M-Li-SiOx displays a prominent improvement of ICE from 58.73%to 88.2%.The graphite/M-Li-SiOx(8:2)composite electrode delivers a.discharge capacity of 497.29 mAh·g^(-1) with an ICE of 91.79%.By pairing graphite/M-Li-SiOx anode and LiFeP04 cathode in a full-cell an enhancement of energy density of 37.25%is realized compared with the full-cell containing graphite/SiOx anode.Furthermore,,ex-situ X-ray photoelectron spectroscopy(XPS)/Raman/X-ray diffraction(XRD)and related electrochemical measurements reveal the SiOx core and Si of M-Li-SiOx participate in the lithiation,and pre-generated Li2Si20s with u+diffusivity and pomegranate-like.structure reduces the reaction resistance and interface impedance of the solid electrolyte interphase(SEI)film.
基金supported by the National Natural Science Foundation of China(21905306,21975289,U19A2019)Hunan Province Natural Science Foundation(2020JJ5694)+1 种基金Hunan Provincial Science and Technology Plan Project of China(2017TP1001,2020JJ2042)Fundamental Research Funds for the Central South University(2020zzts060).
文摘Carbonaceous materials for lithium(Li)/sodium(Na)-ion batteries have attracted significant attention because of their widespread availability,renewable nature,and low cost.During the past decades,although great efforts have been devoted to developing high-performance carbonaceous materials with high capacity,long life span,and excellent rate capability,the low initial Coulombic efficiency(ICE)of high-capacity carbonaceous materials seriously limits their practical applications.Various methods have been successfully exploited,and a revolutionary impact has been achieved through the utilization of different techniques.Different carbonaceous materials possess different ion storage mechanisms,which means that the initial capacity loss may vary.However,there has rarely been a special review about the origins of and progress in the ICE for carbonaceous materials from the angle of the crystal structure.Hence,in this review,the structural differences between and ion storage mechanisms of various carbonaceous materials are first introduced.Then,we deduce the correlative factors of low ICE and thereafter summarize the proposed strategies to address these issues.Finally,some challenges,perspectives,and future directions on the ICE of carbonaceous materials are given.This review will provide deep insights into the challenges of improving the ICE of carbonaceous anodes for high-energy Li/Na-ion batteries,which will greatly contribute to their commercialization process.
基金the financial support from the National Key Research and Development Program of China(Nos.2022YFB2404300 and 2023YFB3809303)the National Natural Science Foundation of China(Nos.51832004 and 52127816)State Key Laboratory of Advanced Technology for Materials Synthesis and Processing(No.WUT:2022-KF-4).
文摘Industrially prepared artificial graphite(AG)is attractive for potassium-ion batteries(PIBs),but its rate performance is poor and the production process is energy intensive,so developing an efficient strategy to produce novel graphite with low energy consumption and high performance is economically important.Herein,a nanostructured graphite composed of multi-walled carbon nanotubes(MWCNTs)and graphite shells was prepared by one-pot method through low-temperature pyrolysis of iron-based metal-organic framework(MOF)and carbon source.The high graphitization degree of nanostructured graphite makes the initial Coulombic efficiency(ICE)exceed 80%,and the three-dimensional(3D)conductive network ensures a specific capacity of 234 mAh·g^(−1)after 1000 cycles at a high current density of 500 mA·g^(−1).In addition,the typical graphite potassium storage mechanism is also demonstrated by in situ X-ray diffraction(XRD)and in situ Raman spectroscopy,and its practicality is also proved by the voltage of the full cells.This work provides a feasible way to optimize the practical production process of AG and expand its application in energy storage.
