Lithium-rich manganese-based oxides(LRMOs;xLi_(2)MnO_(3)(1−x)LiMO_(2);M=transition metal,0<x<1)with excellent specific capacity(>300 mAh/g)and high operating voltage(≥4.8V)are the preferred cathode materials...Lithium-rich manganese-based oxides(LRMOs;xLi_(2)MnO_(3)(1−x)LiMO_(2);M=transition metal,0<x<1)with excellent specific capacity(>300 mAh/g)and high operating voltage(≥4.8V)are the preferred cathode materials for high-specific-energy lithium metal batteries(LMBs)[1].However,LRMOs face a series of serious problems such as irreversible lattice oxygen loss,transition metal(TM)migration,phase transfer,and interfacial side reactions at high voltages,resulting in rapid decay of capacity and voltage[2,3].In situ generating well-functional CEI through electrolyte engineering can effectively address these challenges[4].展开更多
As a potential candidate for high-energy lithium-ion batteries (LIBs),nickel-rich cathodes encounter significant challenges due to structural instability arising from interphases.In this work,tris(ethenyl)-tris(etheny...As a potential candidate for high-energy lithium-ion batteries (LIBs),nickel-rich cathodes encounter significant challenges due to structural instability arising from interphases.In this work,tris(ethenyl)-tris(ethenyl)silyloxysilane (HVDS) with Si–O bonds and unsaturated bonds is introduced as additive designing functional electrolyte to enhance the long-cycle stability of LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)(NCM811)/graphite LIBs at elevated temperature.The preferential oxidization and component of HVDS facilitate the generation of an extremely robust and ultra-thin cathode electrolyte interphase (CEI) comprising a chemically bonded silane polymer.This interphase effectively suppresses side-reactions of electrolyte,mitigates HF erosion,and reduces irreversible phase transitions.Benefiting from the above merits,the batteries’capacity retention shows a remarkable increase from 20% to 92% after nearly 1550 cycles conducted at room temperature.And under elevated temperature conditions (45℃),the capacity retention remains 80%after 670 cycles,in comparison to a drop to 80%after only 250 cycles with the blank electrolyte.These findings highlight HVDS’s potential to functionalize the electrolyte,marking a breakthrough in improving the longevity and reliability of NCM811/graphite LIBs under challenging conditions.展开更多
Dual-ion battery(DIB) composed of graphite cathode and lithium anode is regarded as an advanced secondary battery because of the low cost, high working voltage and environmental friendliness. However,DIB operated at h...Dual-ion battery(DIB) composed of graphite cathode and lithium anode is regarded as an advanced secondary battery because of the low cost, high working voltage and environmental friendliness. However,DIB operated at high potential(usually ≥ 4.5 V versus Li+/Li) is confronted with severe challenges including electrolyte decomposition on cathode interface, and structural deterioration of graphite accompanying with anions de-/intercalation, hinder its cyclic life. To address those drawbacks and preserve the DIB virtues, a feasible and scalable surface modification is achieved for the commercial graphite cathode of mesocarbon microbead. In/ex-situ studies reveal that, such an interfacial engineering facilitates and reconstructs the formation of chemically stable cathode electrolyte interphase with better flexibility alleviating the decomposition of electrolyte, regulating the anions de-/intercalation behavior in graphite with the retainment of structural integrity and without exerting considerable influence on kinetics of anions diffusion. As a result, the modified mesocarbon microbead exhibits a much-extended cycle life with high capacity retention of 82.3% even after 1000 cycles. This study demonstrates that the interface modification of electrode and coating skeleton play important roles on DIB performance improvement, providing the feasible basis for practical application of DIB owing to the green and scalable coating procedures.展开更多
B-containing electrolyte additives are widely used to enhance the cycle performance at low temperature and the rate capability of lithium-ion batteries by constructing an efficient cathode electrolyte interphase(CEI)t...B-containing electrolyte additives are widely used to enhance the cycle performance at low temperature and the rate capability of lithium-ion batteries by constructing an efficient cathode electrolyte interphase(CEI)to facilitate the rapid Li+migration.Nevertheless,its wide-temperature application has been limited by the instability of B-derived CEI layer at high temperature.Herein,dual electrolyte additives,consisting of lithium tetraborate(Li_(2)TB)and 2,4-difluorobiphenyl(FBP),are proposed to boost the widetemperature performances of LiNi_(0.6)Co_(0.2)Mn_(0.2)O_(2)(NCM)cathode.Theoretical calculation and electrochemical performances analyses indicate that Li_(2)TB and FBP undergo successive decomposition to form a unique dual-layer CEI.FBP acts as a synergistic filming additive to Li_(2)TB,enhancing the hightemperature performance of NCM cathode while preserving the excellent low-temperature cycle stability and the superior rate capability conferred by Li_(2)TB additive.Therefore,the capacity retention of NCM‖Li cells using optimal FBP-Li_(2)TB dual electrolyte additives increases to 100%after 200 cycles at-10℃,99%after 200 cycles at 25℃,and 83%after 100 cycles at 55℃,respectively,much superior to that of base electrolyte(63%/69%/45%).More surprisingly,galvanostatic c ha rge/discharge experiments at different temperatures reveal that NCM‖Li cells using FBP-Li_(2)TB additives can operate at temperatures ranging from-40℃to 60℃.This synergistic interphase modification utilizing dual electrolyte additives to construct a unique dual-layer CEI adaptive to a wide temperature range,provides valuable insights to the practical applications of NCM cathodes for all-climate batteries.展开更多
Cathode electrolyte interphase(CEI)has a significant impact on the performance of rechargeable batteries and is gaining increasing attention.Understanding the fundamental and detailed CEI formation mechanism is of cri...Cathode electrolyte interphase(CEI)has a significant impact on the performance of rechargeable batteries and is gaining increasing attention.Understanding the fundamental and detailed CEI formation mechanism is of critical importance for battery chemistry.Herein,a diverse of characterization tools are utilized to comprehensively analyze the composition of the CEI layer as well as its formation mechanism by LiCoO_(2)(LCO)cathode.We reveal that CEI is mainly composed of the reduction products of electrolyte and it only parasitizes the degraded LCO surface which has transformed into a disordered spinel structure due to oxygen loss and lithium depletion.Based on the energy diagram and the chemical potential analysis,the CEI formation process has been well explained,and the proposed CEI formation mechanism is further experimentally validated.This work highlights that the CEI formation process is nearly identical to that of the anode-electrolyte-interphase,both of which are generated due to the electrolyte directly in contact with the low chemical potential electrode material.This work can deepen and refresh our understanding of CEI.展开更多
Ni-rich lithium nickel–cobalt-manganese oxides(NCM) are considered the most promising cathode materials for lithium-ion batteries(LIBs);however, relatively poor cycling performance is a bottleneck preventing their wi...Ni-rich lithium nickel–cobalt-manganese oxides(NCM) are considered the most promising cathode materials for lithium-ion batteries(LIBs);however, relatively poor cycling performance is a bottleneck preventing their widespread use in energy systems. In this work, we propose the use of a dually functionalized surface modifier, calcium sulfate(CaSO_(4), CSO), in an efficient one step method to increase the cycling performance of Ni-rich NCM cathode materials. Thermal treatment of LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)(NCM811) cathode materials with a CSO precursor allows the formation of an artificial Ca-and SO_(x)-functionalized cathode–electrolyte interphase(CEI) layer on the surface of Ni-rich NCM cathode materials. The CEI layer then inhibits electrolyte decomposition at the interface between the Ni-rich NCM cathode and the electrolyte. Successful formation of the CSO-modified CEI layer is confirmed by scanning electron microscopy(SEM) and Fourier transform infrared(FTIR) spectroscopy analyses, and the process does not affect the bulk structure of the Ni-rich NCM cathode material. During cycling, the CSO-modified CEI layer remarkably decreases electrolyte decomposition upon cycling at both room temperature and 45 ℃, leading to a substantial increase in cycling retention of the cells. A cell cycled with a 0.1 CSO-modified(modified with 0.1% CSO)NCM811 cathode exhibits a specific capacity retention of90.0%, while the cell cycled with non-modified NCM811 cathode suffers from continuous fading of cycling retention(74.0%) after 100 cycles. SEM, electrochemical impedance spectroscopy(EIS), X-ray photoelectron spectroscopy(XPS), and inductively coupled plasma mass spectrometry(ICP-MS) results of the recovered electrodes demonstrate that undesired surface reactions such as electrolyte decomposition and metal dissolution are well controlled in the cell because of the artificial CSO-modified CEI layer present on the surface of Ni-rich NCM811 cathodes.展开更多
Ethers are promising electrolyte solvents for secondary Li metal batteries because of their excellent reduction stability.However,their oxidation stability has been mostly relying on the high concentration approach,an...Ethers are promising electrolyte solvents for secondary Li metal batteries because of their excellent reduction stability.However,their oxidation stability has been mostly relying on the high concentration approach,and limited progress has been made on building effective interphase to protect the cathode from the corrosion of the electrolyte.In this work,we construct a semi-crystalline interfacial layer on the surface of Li(Ni_(0.8)Co_(0.1)Mn_(0.1))O_(2)cathode that can achieve improved electrochemical stability in the highly corrosive chemical environment formed by the decomposition of ether molecules.Different from traditional brittle crystalline interphases,the optimized semi-crystalline layer with low modulus and high ionic conductivity can effectively relieve electrode strain and maintain the integrity of the interface layer.Due to this design,the continuous oxidation decomposition of ether-based electrolytes could be significantly suppressed and the battery shows outstanding cycling stability(84%capacity retention after 300 cycles).This article provides a solution to address the oxidation instability issue of ether-based electrolytes.展开更多
Nickel-rich LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)(NCM811)is regarded as the promising cathode for lithium-ion batteries(LIBs).However,the challenges such as safety issues and poor cycling performance have seriously hindered...Nickel-rich LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)(NCM811)is regarded as the promising cathode for lithium-ion batteries(LIBs).However,the challenges such as safety issues and poor cycling performance have seriously hindered its commercial applications.In order to overcome these difficulties,there has been extensive research and development of electrolyte modifications for high-energy-density LIBs with Ni-rich cathodes.Herein,this review introduces the research progress based on solvent additives,salt type additives and other electrolytes for LIBs with NCM811cathode materials and discusses how they control the interface stability.In particular,some recommendations for further modification of enhancing electrolyte stability and improving NCM811 electrochemical properties are summarized and proposed,which put forward new design rules for the screening and customizing ideal electrolyte additives for high performance NCM811 cathode-based LIBs.展开更多
Li metal batteries using high-voltage layered oxides cathodes are of particular interest due to their high energy density.However,they suffer from short lifespan and extreme safety concerns,which are attributed to the...Li metal batteries using high-voltage layered oxides cathodes are of particular interest due to their high energy density.However,they suffer from short lifespan and extreme safety concerns,which are attributed to the degradation of layered oxides and the decomposition of electrolyte at high voltage,as well as the high reactivity of metallic Li.The key is the development of stable electrolytes against both highvoltage cathodes and Li with the formation of robust interphase films on the surfaces.Herein,we report a highly fluorinated ether,1,1,1-trifluoro-2-[(2,2,2-trifluoroethoxy)methoxy]ethane(TTME),as a cosolvent,which not only functions as a diluent forming a localized high concentration electrolyte(LHCE),but also participates in the construction of the inner solvation structure.The TTME-based electrolyte is stable itself at high voltage and induces the formation of a unique double-layer solid electrolyte interphase(SEI)film,which is embodied as one layer rich in crystalline structural components for enhanced mechanical strength and another amorphous layer with a higher concentration of organic components for enhanced flexibility.The Li||Cu cells display a noticeably high Coulombic efficiency of 99.28%after 300 cycles and Li symmetric cells maintain stable cycling more than 3200 h at 0.5 mA/cm^(2) and 1.0m Ah/cm^(2).In addition,lithium metal cells using LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2) and Li CoO_(2) cathodes(both loadings~3.0 m Ah/cm^(2))realize capacity retentions of>85%over 240 cycles with a charge cut-off voltage of 4.4 V and 90%for 170 cycles with a charge cut-off voltage of 4.5 V,respectively.This study offers a bifunctional ether-based electrolyte solvent beneficial for high-voltage Li metal batteries.展开更多
The battery energy density can be improved by raising the operating voltage,however,which may lead to rapid capacity decay due to the continuous electrolyte decomposition and the thickening of electrode electrolyte in...The battery energy density can be improved by raising the operating voltage,however,which may lead to rapid capacity decay due to the continuous electrolyte decomposition and the thickening of electrode electrolyte interphases.To address these challenges,we proposed tripropyl phosphate(TPP)as an additive-regulating Li~+solvation structure to construct a stable Li F–rich electrode carbonate-based electrolyte interphases for sustaining 4.6 V Li||LiCoO_(2)batteries.This optimized interphases could help reduce the resistance and achieve better rate performance and cycling stability.As expected,the Li||LiCoO_(2)battery retained 79.4%capacity after 100 cycles at 0.5 C,while the Li||Li symmetric cell also kept a stable plating/stripping process over 450 h at the current density of 1.0 mA/cm^(2)with a deposited amount of0.5 mAh/cm^(2).展开更多
The growing need for higher energy density in rechargeable batteries necessitates the exploration of cathode materials with enhanced specific energy for lithium-ion batteries.Due to their exceptional cost-effectivenes...The growing need for higher energy density in rechargeable batteries necessitates the exploration of cathode materials with enhanced specific energy for lithium-ion batteries.Due to their exceptional cost-effectiveness and specific capacity,lithium-rich manganese-based cathode materials(LRMs)obtain in-creasing attention in the pursuit of enhancing energy density and reducing costs.The implementation has faced obstacles in various applications due to substantial capacity and voltage degradation,insufficient safety performance,and restricted rate capability during cycling.These issues arise from the migration of transition metal,the release of oxygen,and structural transformation.In this review,we provide an integrated survey of the structure,lithium storage mechanism,challenges,and origins of LRMs,as well as recent advancements in various coating strategies.Particularly,the significance of optimizing the design of the cathode electrolyte interphase was emphasized to enhance electrode performance.Furthermore,future perspective was also addressed alongside in-situ measurements,advanced synthesis techniques,and the application of machine learning to overcome encountered challenges in LRMs.展开更多
Lithium metal batteries (LMBs) show great potential in delivering high energy density (>500 Wh/kg) with cycling [1]. The cycling life of LMBs is mainly improved by regulating the composition and structure of solid/...Lithium metal batteries (LMBs) show great potential in delivering high energy density (>500 Wh/kg) with cycling [1]. The cycling life of LMBs is mainly improved by regulating the composition and structure of solid/cathode electrolyte interphase(SEI/CEI) with electrolytes [2]. However, both Li anode and transition metal oxide cathode have high interfacial reactivity at extreme voltages, which highly needs compatible electrolytes.Recently, localized high-concentration electrolytes (LHCEs) have promisingly stabilized the dual electrodes of high-voltage LMBs[3].展开更多
Spinel LiNi_(0.5)Mn_(1.5)O_(4)(LNMO)cathode draws significant attention in the field of energy storage due to its unique voltage plateau.To further enhance the long-term electrochemical stability of LNMO,the LNMO cath...Spinel LiNi_(0.5)Mn_(1.5)O_(4)(LNMO)cathode draws significant attention in the field of energy storage due to its unique voltage plateau.To further enhance the long-term electrochemical stability of LNMO,the LNMO cathode covered with an ultrathin ZrO_(2)layer was prepared through atomic layer deposition(ALD).It is found that the LNMO cathode deposited with 20 layers of ZrO_(2)(LNMOZ20)exhibits the best electrochemical performance,achieving a high discharge capacity of 117.1 mA·h/g,with a capacity retention of 87.4%after 600 cycles at a current density of 1C.Furthermore,even at higher current densities of 5C and 10C,the LNMOZ20 electrode still demonstrates excellent stability with discharge capacities reaching 111.7 and 103.6 mA·h/g,and capacity retentions maintaining at 81.0%and 101.4%after 2000 cycles,respectively.This study highlights that the incorporation of an ultrathin ZrO_(2)layer by ALD is an effective strategy for enhancing the long-term cycling stability of LNMO cathodes.展开更多
The global shift towards low-carbon energy storage has increased interest in sodium-ion batteries(SIBs)as a safer,cost-effective alternative to lithium-ion batteries.However,the commercial viability has been limited b...The global shift towards low-carbon energy storage has increased interest in sodium-ion batteries(SIBs)as a safer,cost-effective alternative to lithium-ion batteries.However,the commercial viability has been limited by compatibility issues between high-energy-density cathode materials,such as Na_(3)V_(2)(PO_(4))_(2)F_(3)(NVPF),and high-voltage electrolytes.Addressing the challenges,H-NaODFB(comprising 93.91%NaODFB and 5.85%NaBF_(4))electrolyte significantly improves the electrochemical performance and stability of NVPF cathodes,Na/NVPF half-cells using H-NaODFB electrolyte retained 92.4%capacity after 900cycles,while Na/Na symmetric cells demonstrated a cycle life exceeding 600 h at 0.5 mA cm^(-2).The superior performance is attributed to improved Na^(+)(de)intercalation reversibility,lower interfacial impedance(619.8 vs.10,650.0Ω),and faster reaction kinetics compared to NaODFB alone.Advanced time of flight-secondary ion mass spectrometry(TOF-SIMS),X-ray photoelectron spectroscopy(XPS)and aberration corrected transmission electron microscope(AC-TEM),combined with first-principles calculations,revealed that NaBF_(4)in the H-NaODFB electrolyte plays a critical role in forming a stable cathode electrolyte interphase(CEI).The CEI consists of an initial inorganic and organic layer,followed by a fluoroborate layer,and finally a stable organic-inorganic polymeric layer,enhancing electrode stability and preventing over-oxidation.These findings provide valuable insights for designing high-performance electrolytes for SIBs.展开更多
Organic cathode materials present a promising alternative for the inorganic counterparts in conventional lithiumion batteries(LIBs)due to lower cost,reduced environmental impact,renewability,and enhanced energy densit...Organic cathode materials present a promising alternative for the inorganic counterparts in conventional lithiumion batteries(LIBs)due to lower cost,reduced environmental impact,renewability,and enhanced energy density.However,their practical application is hindered by dissolution in electrolytes,structural degradation,and sluggish lithium-ion transport.In this study,we introduce fluoroethylene carbonate(FEC)as an electrolyte additive to engineer a protective cathode–electrolyte interphase(CEI)layer,effectively mitigating cathode pulverization and enhancing battery stability of the organic cathode material,dilithium salt of 2,5-dihydroxy-1,4-benzoquinone(Li_(2)DHBQ).Electrochemical,morphological,and compositional analyses,including cyclic voltammetry(CV),electrochemical impedance spectroscopy(EIS),scanning electron microscopy(SEM),transmission electron microscopy(TEM),and X-ray photoelectron spectroscopy(XPS),confirm that an optimal 1%FEC concentration forms a uniform CEI layer,significantly improving structural integrity and reducing interfacial resistance.Consequently,the battery with 1%FEC retains 185 mAh·g^(−1) after 200 cycles at 500 mA·g^(−1),with a capacity decay rate of just 0.049%per cycle,compared to 81 mAh·g^(−1) and 0.302%per cycle for the FEC-free battery.Additionally,the 1%FEC battery exhibits a capacitive charge storage contribution of up to 93.7%,resulting in excellent rate performance.These findings underscore the crucial role of CEI engineering in stabilizing organic cathodes,offering a practical approach to achieving high-rate and long-cycle LIBs.展开更多
Application of sodium-ion batteries is suppressed due to the lack of appropriate electrolytes matching cathode and anode simultaneously.Ether-based electrolytes,preference of anode materials,cannot match with high-pot...Application of sodium-ion batteries is suppressed due to the lack of appropriate electrolytes matching cathode and anode simultaneously.Ether-based electrolytes,preference of anode materials,cannot match with high-potential cathodes failing to apply in full cells.Herein,vinylene carbonate(VC)as an additive into NaCF_(3) SO_(3)-Diglyme(DGM)could make sodium-ion full cells applicable without preactivation of cathode and anode.The assembled FeS@C||Na3 V2(PO_(4))_(3)@C full cell with this electrolyte exhibits long term cycling stability and high capacity retention.The deduced reason is additive VC,whose HOMO level value is close to that of DGM,not only change the solvent sheath structure of Na^(+),but also is synergistically oxidized with DGM to form integrity and consecutive cathode electrolyte interphase on Na3 V2(PO_(4))_(3)@C cathode,which could effectively improve the oxidative stability of electrolyte and prevent the electrolyte decomposition.This work displays a new way to optimize the sodium-ion full cell seasily with bright practical application potential.展开更多
Li metal batteries(LMBs)with LiNi_(0.8)Mn_(0.1)Co_(0.1)O_(2)(NMC811)cathodes could release a specific energy of>500 Wh kg^(-1) by increasing the charge voltage.However,high-nickel cathodes working at high voltages ...Li metal batteries(LMBs)with LiNi_(0.8)Mn_(0.1)Co_(0.1)O_(2)(NMC811)cathodes could release a specific energy of>500 Wh kg^(-1) by increasing the charge voltage.However,high-nickel cathodes working at high voltages accelerate degradations in bulk and at interfaces,thus significantly degrading the cycling lifespan and decreasing the specific capacity.Here,we rationally design an all-fluorinated electrolyte with addictive tri(2,2,2-trifluoroethyl)borate(TFEB),based on 3,3,3-fluoroethylmethylcarbonate(FEMC)and fluoroethylene carbonate(FEC),which enables stable cycling of high nickel cathode(LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2),NMC811)under a cut-off voltage of 4.7 V in Li metal batteries.The electrolyte not only shows the fire-extinguishing properties,but also inhibits the transition metal dissolution,the gas production,side reactions on the cathode side.Therefore,the NMC811||Li cell demonstrates excellent performance by using limited Li and high-loading cathode,delivering a specific capacity>220 mA h g^(-1),an average Coulombic efficiency>99.6%and capacity retention>99.7%over 100 cycles.展开更多
As promising candidates for high-energy-density lithium-ion batteries,both silicon(Si)anodes and nickel-rich cathodes face significant challenges due to structural instability arising from interphases.In this study,we...As promising candidates for high-energy-density lithium-ion batteries,both silicon(Si)anodes and nickel-rich cathodes face significant challenges due to structural instability arising from interphases.In this study,we introduced tetravinylsilane(TVSi)as a multifunctional electrolyte additive to engineer tai-lored interphases simultaneously on Si anode and LiNi_(0.92)Mn_(0.05)Co_(0.03)O_(2)cathode,thereby enhancing their electrochemical performance.On one front,TVSi underwent polymerization,leading to the for-mation of a composite solid electrolyte interphase(SEI)with an interpenetrating network structure on the Si surface.This SEI effectively accommodated volume changes during cycling,which inhibited SEI growth,hence,preserving the battery capacity.On the other hand,the TVSi-induced cathode electrolyte interphase(CEI)exhibited a dense structure com-prising a chemically bonded silicate-silane polymer.This CEI effectively mitigated transition metal disso-lution by scavenging hydrofluoric acid(HF)and re-duced irreversible phase transitions by minimizing side reactions.As a result of the enhanced interfacial stability achieved on both electrodes,TVSi enabled improved performance in full cells fabricated with a LiNi_(0.92)Mn_(0.05)Co_(0.03)O_(2)cathode paired with a Si anode.This multifunctional additive strategy offers a novel perspective on additive design for high-energy-density lithium-ion batteries,showcasing its potential for advancing battery technology.展开更多
Ni-rich layered oxides are attractive cathode materials for advanced lithium-ion batteries(LIBs)due to their high energy density.However,their large-scale application is seriously hindered by their interfacial instabi...Ni-rich layered oxides are attractive cathode materials for advanced lithium-ion batteries(LIBs)due to their high energy density.However,their large-scale application is seriously hindered by their interfacial instability,especially at a high cut-off potential.Here,we demonstrate that trimethoxyboroxine(TMOBX)is an effective film-forming additive to address the interfacial instability of LiNi0.8Co0.1Mn0.1O_(2)(NCM811)material at a high cut-off voltage of 4.5V.We find that TMOBX decomposes before carbonate solvent and forms a thin cathode electrolyte interphase(CEI)layer on the surface of the NCM811 material.This TMOBX-formed CEI significantly suppresses electrolyte decomposition at a high potential and inhibits the dissolution of transition metals from NCM811 during cycling.In addition,electron-deficient borate compounds coordinate with anions(PF6^(−),F^(-) etc.)and H2O in the battery,further improving the battery's stability.As a result,adding 1.0wt%of TMOBX boosts the capacity retention of a Li||NCM811cell from 68.72%to 86.60%after 200 cycles at 0.5C in the range of 2.8–4.5V.展开更多
The construction of stable cathode electrolyte interphase(CEI)is the key to improve the NCM811 particle structure and interfacial stability via electrolyte engineering.In He’s work,lithium hexamethyldisilazide(LiHMDS...The construction of stable cathode electrolyte interphase(CEI)is the key to improve the NCM811 particle structure and interfacial stability via electrolyte engineering.In He’s work,lithium hexamethyldisilazide(LiHMDS)as the electrolyte additive is proposed to facilitate the generation of stable CEI on NCM811 cathode surface and eliminate H_(2)O and HF in the electrolyte at the same time,which boosts the cycling performance of Li||NCM811 battery up to 1000 or 500 cycles with 4.5 V cut-off voltage at 25 or 60℃.展开更多
文摘Lithium-rich manganese-based oxides(LRMOs;xLi_(2)MnO_(3)(1−x)LiMO_(2);M=transition metal,0<x<1)with excellent specific capacity(>300 mAh/g)and high operating voltage(≥4.8V)are the preferred cathode materials for high-specific-energy lithium metal batteries(LMBs)[1].However,LRMOs face a series of serious problems such as irreversible lattice oxygen loss,transition metal(TM)migration,phase transfer,and interfacial side reactions at high voltages,resulting in rapid decay of capacity and voltage[2,3].In situ generating well-functional CEI through electrolyte engineering can effectively address these challenges[4].
基金financially supported by the Scientific Research Innovation Project of Graduate School of South China Normal University (No. 2024KYLX081)。
文摘As a potential candidate for high-energy lithium-ion batteries (LIBs),nickel-rich cathodes encounter significant challenges due to structural instability arising from interphases.In this work,tris(ethenyl)-tris(ethenyl)silyloxysilane (HVDS) with Si–O bonds and unsaturated bonds is introduced as additive designing functional electrolyte to enhance the long-cycle stability of LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)(NCM811)/graphite LIBs at elevated temperature.The preferential oxidization and component of HVDS facilitate the generation of an extremely robust and ultra-thin cathode electrolyte interphase (CEI) comprising a chemically bonded silane polymer.This interphase effectively suppresses side-reactions of electrolyte,mitigates HF erosion,and reduces irreversible phase transitions.Benefiting from the above merits,the batteries’capacity retention shows a remarkable increase from 20% to 92% after nearly 1550 cycles conducted at room temperature.And under elevated temperature conditions (45℃),the capacity retention remains 80%after 670 cycles,in comparison to a drop to 80%after only 250 cycles with the blank electrolyte.These findings highlight HVDS’s potential to functionalize the electrolyte,marking a breakthrough in improving the longevity and reliability of NCM811/graphite LIBs under challenging conditions.
基金the financial support from the National Natural Science Foundation of China(91963118)the Fundamental Research Funds for the Central Universities(2412019ZD010)。
文摘Dual-ion battery(DIB) composed of graphite cathode and lithium anode is regarded as an advanced secondary battery because of the low cost, high working voltage and environmental friendliness. However,DIB operated at high potential(usually ≥ 4.5 V versus Li+/Li) is confronted with severe challenges including electrolyte decomposition on cathode interface, and structural deterioration of graphite accompanying with anions de-/intercalation, hinder its cyclic life. To address those drawbacks and preserve the DIB virtues, a feasible and scalable surface modification is achieved for the commercial graphite cathode of mesocarbon microbead. In/ex-situ studies reveal that, such an interfacial engineering facilitates and reconstructs the formation of chemically stable cathode electrolyte interphase with better flexibility alleviating the decomposition of electrolyte, regulating the anions de-/intercalation behavior in graphite with the retainment of structural integrity and without exerting considerable influence on kinetics of anions diffusion. As a result, the modified mesocarbon microbead exhibits a much-extended cycle life with high capacity retention of 82.3% even after 1000 cycles. This study demonstrates that the interface modification of electrode and coating skeleton play important roles on DIB performance improvement, providing the feasible basis for practical application of DIB owing to the green and scalable coating procedures.
基金supported by the National Natural Science Foundation of China(No.21972049)。
文摘B-containing electrolyte additives are widely used to enhance the cycle performance at low temperature and the rate capability of lithium-ion batteries by constructing an efficient cathode electrolyte interphase(CEI)to facilitate the rapid Li+migration.Nevertheless,its wide-temperature application has been limited by the instability of B-derived CEI layer at high temperature.Herein,dual electrolyte additives,consisting of lithium tetraborate(Li_(2)TB)and 2,4-difluorobiphenyl(FBP),are proposed to boost the widetemperature performances of LiNi_(0.6)Co_(0.2)Mn_(0.2)O_(2)(NCM)cathode.Theoretical calculation and electrochemical performances analyses indicate that Li_(2)TB and FBP undergo successive decomposition to form a unique dual-layer CEI.FBP acts as a synergistic filming additive to Li_(2)TB,enhancing the hightemperature performance of NCM cathode while preserving the excellent low-temperature cycle stability and the superior rate capability conferred by Li_(2)TB additive.Therefore,the capacity retention of NCM‖Li cells using optimal FBP-Li_(2)TB dual electrolyte additives increases to 100%after 200 cycles at-10℃,99%after 200 cycles at 25℃,and 83%after 100 cycles at 55℃,respectively,much superior to that of base electrolyte(63%/69%/45%).More surprisingly,galvanostatic c ha rge/discharge experiments at different temperatures reveal that NCM‖Li cells using FBP-Li_(2)TB additives can operate at temperatures ranging from-40℃to 60℃.This synergistic interphase modification utilizing dual electrolyte additives to construct a unique dual-layer CEI adaptive to a wide temperature range,provides valuable insights to the practical applications of NCM cathodes for all-climate batteries.
基金Natural Science Foundation of Beijing,China,Grant/Award Number:2212003National Natural Science Foundation of China for Youth Science Fund,Grant/Award Number:12204025+2 种基金National Natural Science Fund for Innovative Research Groups,Grant/Award Number:51621003Beijing municipal high level innovative team building program,Grant/Award Number:IDHT20190503The U.S.Department of Energy(DOE),Office of Science,Basic Energy Sciences,Division of Materials Sciences and Engineering,Synthesis and Processing Science Program,Grant/Award Number:10122。
文摘Cathode electrolyte interphase(CEI)has a significant impact on the performance of rechargeable batteries and is gaining increasing attention.Understanding the fundamental and detailed CEI formation mechanism is of critical importance for battery chemistry.Herein,a diverse of characterization tools are utilized to comprehensively analyze the composition of the CEI layer as well as its formation mechanism by LiCoO_(2)(LCO)cathode.We reveal that CEI is mainly composed of the reduction products of electrolyte and it only parasitizes the degraded LCO surface which has transformed into a disordered spinel structure due to oxygen loss and lithium depletion.Based on the energy diagram and the chemical potential analysis,the CEI formation process has been well explained,and the proposed CEI formation mechanism is further experimentally validated.This work highlights that the CEI formation process is nearly identical to that of the anode-electrolyte-interphase,both of which are generated due to the electrolyte directly in contact with the low chemical potential electrode material.This work can deepen and refresh our understanding of CEI.
基金financially supported by the National Research Foundation of Korea(NRF)(Nos.NRF2019R1C1C1002249 and NRF-2017R1A6A1A06015181)the Technology Innovation Program(Nos.20010095 and 20011905)funded by the Ministry of Trade,Industry&Energy(MOTIE,Korea)。
文摘Ni-rich lithium nickel–cobalt-manganese oxides(NCM) are considered the most promising cathode materials for lithium-ion batteries(LIBs);however, relatively poor cycling performance is a bottleneck preventing their widespread use in energy systems. In this work, we propose the use of a dually functionalized surface modifier, calcium sulfate(CaSO_(4), CSO), in an efficient one step method to increase the cycling performance of Ni-rich NCM cathode materials. Thermal treatment of LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)(NCM811) cathode materials with a CSO precursor allows the formation of an artificial Ca-and SO_(x)-functionalized cathode–electrolyte interphase(CEI) layer on the surface of Ni-rich NCM cathode materials. The CEI layer then inhibits electrolyte decomposition at the interface between the Ni-rich NCM cathode and the electrolyte. Successful formation of the CSO-modified CEI layer is confirmed by scanning electron microscopy(SEM) and Fourier transform infrared(FTIR) spectroscopy analyses, and the process does not affect the bulk structure of the Ni-rich NCM cathode material. During cycling, the CSO-modified CEI layer remarkably decreases electrolyte decomposition upon cycling at both room temperature and 45 ℃, leading to a substantial increase in cycling retention of the cells. A cell cycled with a 0.1 CSO-modified(modified with 0.1% CSO)NCM811 cathode exhibits a specific capacity retention of90.0%, while the cell cycled with non-modified NCM811 cathode suffers from continuous fading of cycling retention(74.0%) after 100 cycles. SEM, electrochemical impedance spectroscopy(EIS), X-ray photoelectron spectroscopy(XPS), and inductively coupled plasma mass spectrometry(ICP-MS) results of the recovered electrodes demonstrate that undesired surface reactions such as electrolyte decomposition and metal dissolution are well controlled in the cell because of the artificial CSO-modified CEI layer present on the surface of Ni-rich NCM811 cathodes.
基金supported by the National Natural Science Foundation of China(22179124,21905265)the Fundamental Research Funds for the Central Universities(WK3430000007)。
文摘Ethers are promising electrolyte solvents for secondary Li metal batteries because of their excellent reduction stability.However,their oxidation stability has been mostly relying on the high concentration approach,and limited progress has been made on building effective interphase to protect the cathode from the corrosion of the electrolyte.In this work,we construct a semi-crystalline interfacial layer on the surface of Li(Ni_(0.8)Co_(0.1)Mn_(0.1))O_(2)cathode that can achieve improved electrochemical stability in the highly corrosive chemical environment formed by the decomposition of ether molecules.Different from traditional brittle crystalline interphases,the optimized semi-crystalline layer with low modulus and high ionic conductivity can effectively relieve electrode strain and maintain the integrity of the interface layer.Due to this design,the continuous oxidation decomposition of ether-based electrolytes could be significantly suppressed and the battery shows outstanding cycling stability(84%capacity retention after 300 cycles).This article provides a solution to address the oxidation instability issue of ether-based electrolytes.
基金financially supported by the National Natural Science Foundation of China(Nos.51971090,U21A20311)。
文摘Nickel-rich LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)(NCM811)is regarded as the promising cathode for lithium-ion batteries(LIBs).However,the challenges such as safety issues and poor cycling performance have seriously hindered its commercial applications.In order to overcome these difficulties,there has been extensive research and development of electrolyte modifications for high-energy-density LIBs with Ni-rich cathodes.Herein,this review introduces the research progress based on solvent additives,salt type additives and other electrolytes for LIBs with NCM811cathode materials and discusses how they control the interface stability.In particular,some recommendations for further modification of enhancing electrolyte stability and improving NCM811 electrochemical properties are summarized and proposed,which put forward new design rules for the screening and customizing ideal electrolyte additives for high performance NCM811 cathode-based LIBs.
基金the financial supports from the KeyArea Research and Development Program of Guangdong Province (2020B090919001)the National Natural Science Foundation of China (22078144)the Guangdong Natural Science Foundation for Basic and Applied Basic Research (2021A1515010138 and 2023A1515010686)。
文摘Li metal batteries using high-voltage layered oxides cathodes are of particular interest due to their high energy density.However,they suffer from short lifespan and extreme safety concerns,which are attributed to the degradation of layered oxides and the decomposition of electrolyte at high voltage,as well as the high reactivity of metallic Li.The key is the development of stable electrolytes against both highvoltage cathodes and Li with the formation of robust interphase films on the surfaces.Herein,we report a highly fluorinated ether,1,1,1-trifluoro-2-[(2,2,2-trifluoroethoxy)methoxy]ethane(TTME),as a cosolvent,which not only functions as a diluent forming a localized high concentration electrolyte(LHCE),but also participates in the construction of the inner solvation structure.The TTME-based electrolyte is stable itself at high voltage and induces the formation of a unique double-layer solid electrolyte interphase(SEI)film,which is embodied as one layer rich in crystalline structural components for enhanced mechanical strength and another amorphous layer with a higher concentration of organic components for enhanced flexibility.The Li||Cu cells display a noticeably high Coulombic efficiency of 99.28%after 300 cycles and Li symmetric cells maintain stable cycling more than 3200 h at 0.5 mA/cm^(2) and 1.0m Ah/cm^(2).In addition,lithium metal cells using LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2) and Li CoO_(2) cathodes(both loadings~3.0 m Ah/cm^(2))realize capacity retentions of>85%over 240 cycles with a charge cut-off voltage of 4.4 V and 90%for 170 cycles with a charge cut-off voltage of 4.5 V,respectively.This study offers a bifunctional ether-based electrolyte solvent beneficial for high-voltage Li metal batteries.
基金supported by the National Natural Science Foundation of China(No.U21A20311)the Distinguished Scientist Fellowship Program(DSFP)at King Saud University,Riyadh,Saudi Arabia。
文摘The battery energy density can be improved by raising the operating voltage,however,which may lead to rapid capacity decay due to the continuous electrolyte decomposition and the thickening of electrode electrolyte interphases.To address these challenges,we proposed tripropyl phosphate(TPP)as an additive-regulating Li~+solvation structure to construct a stable Li F–rich electrode carbonate-based electrolyte interphases for sustaining 4.6 V Li||LiCoO_(2)batteries.This optimized interphases could help reduce the resistance and achieve better rate performance and cycling stability.As expected,the Li||LiCoO_(2)battery retained 79.4%capacity after 100 cycles at 0.5 C,while the Li||Li symmetric cell also kept a stable plating/stripping process over 450 h at the current density of 1.0 mA/cm^(2)with a deposited amount of0.5 mAh/cm^(2).
基金the support from the National Natural Science Foun-dation of China(Grant No.U21A20311)the Distinguished Scientist Fellowship Program(DSFP)at King Saud University,Riyadh,Saudi Arabia.
文摘The growing need for higher energy density in rechargeable batteries necessitates the exploration of cathode materials with enhanced specific energy for lithium-ion batteries.Due to their exceptional cost-effectiveness and specific capacity,lithium-rich manganese-based cathode materials(LRMs)obtain in-creasing attention in the pursuit of enhancing energy density and reducing costs.The implementation has faced obstacles in various applications due to substantial capacity and voltage degradation,insufficient safety performance,and restricted rate capability during cycling.These issues arise from the migration of transition metal,the release of oxygen,and structural transformation.In this review,we provide an integrated survey of the structure,lithium storage mechanism,challenges,and origins of LRMs,as well as recent advancements in various coating strategies.Particularly,the significance of optimizing the design of the cathode electrolyte interphase was emphasized to enhance electrode performance.Furthermore,future perspective was also addressed alongside in-situ measurements,advanced synthesis techniques,and the application of machine learning to overcome encountered challenges in LRMs.
文摘Lithium metal batteries (LMBs) show great potential in delivering high energy density (>500 Wh/kg) with cycling [1]. The cycling life of LMBs is mainly improved by regulating the composition and structure of solid/cathode electrolyte interphase(SEI/CEI) with electrolytes [2]. However, both Li anode and transition metal oxide cathode have high interfacial reactivity at extreme voltages, which highly needs compatible electrolytes.Recently, localized high-concentration electrolytes (LHCEs) have promisingly stabilized the dual electrodes of high-voltage LMBs[3].
基金supported by the National Natural Science Foundation of China(Nos.51931006,U22A20118).
文摘Spinel LiNi_(0.5)Mn_(1.5)O_(4)(LNMO)cathode draws significant attention in the field of energy storage due to its unique voltage plateau.To further enhance the long-term electrochemical stability of LNMO,the LNMO cathode covered with an ultrathin ZrO_(2)layer was prepared through atomic layer deposition(ALD).It is found that the LNMO cathode deposited with 20 layers of ZrO_(2)(LNMOZ20)exhibits the best electrochemical performance,achieving a high discharge capacity of 117.1 mA·h/g,with a capacity retention of 87.4%after 600 cycles at a current density of 1C.Furthermore,even at higher current densities of 5C and 10C,the LNMOZ20 electrode still demonstrates excellent stability with discharge capacities reaching 111.7 and 103.6 mA·h/g,and capacity retentions maintaining at 81.0%and 101.4%after 2000 cycles,respectively.This study highlights that the incorporation of an ultrathin ZrO_(2)layer by ALD is an effective strategy for enhancing the long-term cycling stability of LNMO cathodes.
基金financially supported by the Cultivation and Construction of Ten National Science and Technology Innovation Platforms in Qinghai Province(2024-ZJ-J03)Xining Major Science and Technology Innovation Platform Capacity Building Project(2024-Z1)+1 种基金funding from Young Scholars of Western China,Chinese Academy of Sciences(E110HX0501)Qinghai Province Youth Science and Technology Talent Support Project(2022QHSKXRCTJ06)。
文摘The global shift towards low-carbon energy storage has increased interest in sodium-ion batteries(SIBs)as a safer,cost-effective alternative to lithium-ion batteries.However,the commercial viability has been limited by compatibility issues between high-energy-density cathode materials,such as Na_(3)V_(2)(PO_(4))_(2)F_(3)(NVPF),and high-voltage electrolytes.Addressing the challenges,H-NaODFB(comprising 93.91%NaODFB and 5.85%NaBF_(4))electrolyte significantly improves the electrochemical performance and stability of NVPF cathodes,Na/NVPF half-cells using H-NaODFB electrolyte retained 92.4%capacity after 900cycles,while Na/Na symmetric cells demonstrated a cycle life exceeding 600 h at 0.5 mA cm^(-2).The superior performance is attributed to improved Na^(+)(de)intercalation reversibility,lower interfacial impedance(619.8 vs.10,650.0Ω),and faster reaction kinetics compared to NaODFB alone.Advanced time of flight-secondary ion mass spectrometry(TOF-SIMS),X-ray photoelectron spectroscopy(XPS)and aberration corrected transmission electron microscope(AC-TEM),combined with first-principles calculations,revealed that NaBF_(4)in the H-NaODFB electrolyte plays a critical role in forming a stable cathode electrolyte interphase(CEI).The CEI consists of an initial inorganic and organic layer,followed by a fluoroborate layer,and finally a stable organic-inorganic polymeric layer,enhancing electrode stability and preventing over-oxidation.These findings provide valuable insights for designing high-performance electrolytes for SIBs.
基金supported by the Natural Sciences and Engineering Research Council of Canada(NSERC)through the Discovery Grants(No.RGPIN-2022-03835)Alliance Grants(No.ALLRP 581429-23)the Mitacs Accelerate Fellowship(No.IT35432).
文摘Organic cathode materials present a promising alternative for the inorganic counterparts in conventional lithiumion batteries(LIBs)due to lower cost,reduced environmental impact,renewability,and enhanced energy density.However,their practical application is hindered by dissolution in electrolytes,structural degradation,and sluggish lithium-ion transport.In this study,we introduce fluoroethylene carbonate(FEC)as an electrolyte additive to engineer a protective cathode–electrolyte interphase(CEI)layer,effectively mitigating cathode pulverization and enhancing battery stability of the organic cathode material,dilithium salt of 2,5-dihydroxy-1,4-benzoquinone(Li_(2)DHBQ).Electrochemical,morphological,and compositional analyses,including cyclic voltammetry(CV),electrochemical impedance spectroscopy(EIS),scanning electron microscopy(SEM),transmission electron microscopy(TEM),and X-ray photoelectron spectroscopy(XPS),confirm that an optimal 1%FEC concentration forms a uniform CEI layer,significantly improving structural integrity and reducing interfacial resistance.Consequently,the battery with 1%FEC retains 185 mAh·g^(−1) after 200 cycles at 500 mA·g^(−1),with a capacity decay rate of just 0.049%per cycle,compared to 81 mAh·g^(−1) and 0.302%per cycle for the FEC-free battery.Additionally,the 1%FEC battery exhibits a capacitive charge storage contribution of up to 93.7%,resulting in excellent rate performance.These findings underscore the crucial role of CEI engineering in stabilizing organic cathodes,offering a practical approach to achieving high-rate and long-cycle LIBs.
基金supported by the National Natural Science Foundation of China(Nos.U1804129,21771164,21671205,U1804126)Zhongyuan Youth Talent Support Program of Henan ProvinceZhengzhou University Youth Innovation Program。
文摘Application of sodium-ion batteries is suppressed due to the lack of appropriate electrolytes matching cathode and anode simultaneously.Ether-based electrolytes,preference of anode materials,cannot match with high-potential cathodes failing to apply in full cells.Herein,vinylene carbonate(VC)as an additive into NaCF_(3) SO_(3)-Diglyme(DGM)could make sodium-ion full cells applicable without preactivation of cathode and anode.The assembled FeS@C||Na3 V2(PO_(4))_(3)@C full cell with this electrolyte exhibits long term cycling stability and high capacity retention.The deduced reason is additive VC,whose HOMO level value is close to that of DGM,not only change the solvent sheath structure of Na^(+),but also is synergistically oxidized with DGM to form integrity and consecutive cathode electrolyte interphase on Na3 V2(PO_(4))_(3)@C cathode,which could effectively improve the oxidative stability of electrolyte and prevent the electrolyte decomposition.This work displays a new way to optimize the sodium-ion full cell seasily with bright practical application potential.
基金the National Natural Science Foundation of China and the Israeli Science Foundation for funding this research within the framework of the joint NSFC-ISF grant#51961145302supported by China Postdoctoral Science Foundation funded project(Grant#2020M682403).
文摘Li metal batteries(LMBs)with LiNi_(0.8)Mn_(0.1)Co_(0.1)O_(2)(NMC811)cathodes could release a specific energy of>500 Wh kg^(-1) by increasing the charge voltage.However,high-nickel cathodes working at high voltages accelerate degradations in bulk and at interfaces,thus significantly degrading the cycling lifespan and decreasing the specific capacity.Here,we rationally design an all-fluorinated electrolyte with addictive tri(2,2,2-trifluoroethyl)borate(TFEB),based on 3,3,3-fluoroethylmethylcarbonate(FEMC)and fluoroethylene carbonate(FEC),which enables stable cycling of high nickel cathode(LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2),NMC811)under a cut-off voltage of 4.7 V in Li metal batteries.The electrolyte not only shows the fire-extinguishing properties,but also inhibits the transition metal dissolution,the gas production,side reactions on the cathode side.Therefore,the NMC811||Li cell demonstrates excellent performance by using limited Li and high-loading cathode,delivering a specific capacity>220 mA h g^(-1),an average Coulombic efficiency>99.6%and capacity retention>99.7%over 100 cycles.
基金supported by the National Natural Science Foundation of China(NSFCgrant no.52303263)+1 种基金the Shenzhen Science and Technology Research Grants,China(grant no.JCYJ20200109140416788)the Soft Science Research Project of Guangdong Province,China(grant no.2017B030301013).
文摘As promising candidates for high-energy-density lithium-ion batteries,both silicon(Si)anodes and nickel-rich cathodes face significant challenges due to structural instability arising from interphases.In this study,we introduced tetravinylsilane(TVSi)as a multifunctional electrolyte additive to engineer tai-lored interphases simultaneously on Si anode and LiNi_(0.92)Mn_(0.05)Co_(0.03)O_(2)cathode,thereby enhancing their electrochemical performance.On one front,TVSi underwent polymerization,leading to the for-mation of a composite solid electrolyte interphase(SEI)with an interpenetrating network structure on the Si surface.This SEI effectively accommodated volume changes during cycling,which inhibited SEI growth,hence,preserving the battery capacity.On the other hand,the TVSi-induced cathode electrolyte interphase(CEI)exhibited a dense structure com-prising a chemically bonded silicate-silane polymer.This CEI effectively mitigated transition metal disso-lution by scavenging hydrofluoric acid(HF)and re-duced irreversible phase transitions by minimizing side reactions.As a result of the enhanced interfacial stability achieved on both electrodes,TVSi enabled improved performance in full cells fabricated with a LiNi_(0.92)Mn_(0.05)Co_(0.03)O_(2)cathode paired with a Si anode.This multifunctional additive strategy offers a novel perspective on additive design for high-energy-density lithium-ion batteries,showcasing its potential for advancing battery technology.
基金supported by the National Natural Science Foundation of China(Grant nos.21625304 and 21733012).
文摘Ni-rich layered oxides are attractive cathode materials for advanced lithium-ion batteries(LIBs)due to their high energy density.However,their large-scale application is seriously hindered by their interfacial instability,especially at a high cut-off potential.Here,we demonstrate that trimethoxyboroxine(TMOBX)is an effective film-forming additive to address the interfacial instability of LiNi0.8Co0.1Mn0.1O_(2)(NCM811)material at a high cut-off voltage of 4.5V.We find that TMOBX decomposes before carbonate solvent and forms a thin cathode electrolyte interphase(CEI)layer on the surface of the NCM811 material.This TMOBX-formed CEI significantly suppresses electrolyte decomposition at a high potential and inhibits the dissolution of transition metals from NCM811 during cycling.In addition,electron-deficient borate compounds coordinate with anions(PF6^(−),F^(-) etc.)and H2O in the battery,further improving the battery's stability.As a result,adding 1.0wt%of TMOBX boosts the capacity retention of a Li||NCM811cell from 68.72%to 86.60%after 200 cycles at 0.5C in the range of 2.8–4.5V.
基金the support from the National Natural Science Foundation of China(Grant No.51971090 and U21A20311)。
文摘The construction of stable cathode electrolyte interphase(CEI)is the key to improve the NCM811 particle structure and interfacial stability via electrolyte engineering.In He’s work,lithium hexamethyldisilazide(LiHMDS)as the electrolyte additive is proposed to facilitate the generation of stable CEI on NCM811 cathode surface and eliminate H_(2)O and HF in the electrolyte at the same time,which boosts the cycling performance of Li||NCM811 battery up to 1000 or 500 cycles with 4.5 V cut-off voltage at 25 or 60℃.
