LiNiO_(2)(LNO)is one of the most promising cathode materials for lithium-ion batteries.Tungsten element in enhancing the stability of LNO has been researched extensively.However,the understanding of the specific dopin...LiNiO_(2)(LNO)is one of the most promising cathode materials for lithium-ion batteries.Tungsten element in enhancing the stability of LNO has been researched extensively.However,the understanding of the specific doping process and existing form of W are still not perfect.This study proposes a lithium-induced grain boundary phase W doping mechanism.The results demonstrate that the introduced W atomsfirst react with the lithium source to generate a Li–W–O phase at the grain boundary of primary particles.With the increase of lithium ratio,W atoms gradually diffuse from the grain boundary phase to the interior layered structure to achieve W doping.The feasibility of grain boundary phase doping is verified byfirst principles calculation.Furthermore,it is found that the Li2WO4 grain boundary phase is an excellent lithium ion conductor,which can protect the cathode surface and improve the rate performance.The doped W can alleviate the harmful H2↔H3 phase transition,thereby inhibiting the generation of microcracks,and improving the electrochemical performance.Consequently,the 0.3 wt%W-doped sample provides a significant improved capacity retention of 88.5%compared with the pristine LNO(80.7%)after 100 cycles at 2.8–4.3 V under 1C.展开更多
Stress accumulation is a key factor leading to sodium storage performance deterioration for NiSe_(2)-based anodes.Therefore,inhibiting the concentrated local stress during the sodiataion/desodiation process is crucial...Stress accumulation is a key factor leading to sodium storage performance deterioration for NiSe_(2)-based anodes.Therefore,inhibiting the concentrated local stress during the sodiataion/desodiation process is crucial for acquiring stable NiSe2-based materials for sodium-ion batteries(SIBs),Herein,a stress dissipation strategy driven by architecture engineering is proposed,which can achieve ultrafast and ultralong sodium storage properties.Different from the conventional sphere-like or rod-like architecture,the three-dimensional(3D)flower-like NiSe_(2)@C composite is delicately designed and assembled with onedimensional nanorods and carbon framework.More importantly,the fundamental mechanism of improved structure stability is unveiled by simulations and experimental results simultaneously.It demonstrates that this designed multidimensional flower-like architecture with dispersed nanorods can balance the structural mismatch,avoid concentrated local strain,and relax the internal stress,mainly induced by the unavoidable volume variation during the repeated conversion processes.Moreover,it can provide more Na^(+)-storage sites and multi-directional migration pathways,leading to a fast Na^(+)-migration channel with boosted reaction kinetic.As expected,it delivers superior rate performance(441 mA h g^(-1)at 5.0 A g^(-1))and long cycling stability(563 mA h g^(-1)at 1.0 A g^(-1)over 1000 cycles)for SIBs.This work provides useful insights for designing high-performance conversion-based anode materials for SIBs.展开更多
Aqueous zinc-ion batteries(ZIBs)are receiving a continuously increasing attention for mobile devices,especially for the flexible and wearable electronics,due to their non-toxicity,non-flammability,and low-cost feature...Aqueous zinc-ion batteries(ZIBs)are receiving a continuously increasing attention for mobile devices,especially for the flexible and wearable electronics,due to their non-toxicity,non-flammability,and low-cost features.Despite the significant progress in achieving higher capacities for electrode materials of ZIBs,to endow them with high flexibility and economic feasibility is,however,still a significant challenge remaining unsolved.Herein,we present a highly flexible composite film composed of carbon nanotube film and V_(2)O_(5)(CNTF@V_(2)O_(5))with high strength and high conductivity,which is prepared by simply impregnating a porous CNT film with an aqueous V_(2)O_(5)sol under vacuum.For this material,intimate incorporation between V_(2)O_(5)and CNTs has been achieved,successfully integrating the high zinc ion storage capability with high mechanical flexibility.As a result,this CNTF@V_(2)O_(5)film delivers a high capacity of 356.6 m Ah g^(-1)at 0.4 A g^(-1)and excellent cycling stability with 80.1%capacity retention after 500 cycles at 2.0 A g^(-1).The novel strategy and the outstanding battery performance presented in this work should shed light on the development of high-performance and flexible ZIBs.展开更多
Along with the extensive application of energy storage devices,the spent lithium-ion batteries(LIBs)are unquestionably classified into the secondary resources due to its high content of several valuable metals.However...Along with the extensive application of energy storage devices,the spent lithium-ion batteries(LIBs)are unquestionably classified into the secondary resources due to its high content of several valuable metals.However,current recycling methods have the main drawback to their tedious process,especially the purification and separation process.Herein,we propose a simplified process to recycle both cathode(LiCoO_(2))and anode(graphite)in the spent LIBs and regenerate newly high-performance anode material,CoO/CoFe2O4/expanded graphite(EG).This process not only has the advantages of succinct procedure and easy control of reaction conditions,but also effectively separates and recycles lithium from transition metals.The 98.43%of lithium is recovered from leachate when the solid product CoO/CoFe2O4/EG is synthesized as anode material for LIBs.And the product exhibits improved cyclic stability(890 mAh g^(-1) at 1 A g^(-1) after 700 cycles)and superior rate capability(208 mAh g^(-1) at 5 A g^(-1)).The merit of this delicate recycling design can be summarized as three aspects:the utilization of Fe impurity in waste LiCoO_(2),the transformation of waste graphite to EG,and the regeneration of anode material.This approach properly recycles the valuable components of spent LIBs,which introduces an insight into the future recycling.展开更多
In this paper,the ammonia leaching process and high-energy ball milling method were adapted to recover spent LiCoO_(2) material.The ammonia reduction leaching mechanism of LiCoO_(2) material in the ammonia-sodium sulf...In this paper,the ammonia leaching process and high-energy ball milling method were adapted to recover spent LiCoO_(2) material.The ammonia reduction leaching mechanism of LiCoO_(2) material in the ammonia-sodium sulfite-ammonium chloride system was elucidated.Compared with untreated LiCoO_(2) material,the leaching equilibrium time of LiCoO_(2) after ball-milled for 5 h was reduced from 48 h to 4 h,and the leaching efficiency of lithium and cobalt was improved from 69.86%and 70.80%to 89.86%and98.22%,respectively.Importantly,the apparent activation energy and leaching kinetic equation of the reaction was calculated by the shrinking core reaction model,indicating that the reaction was controlled by the chemical reaction.展开更多
Owing to the further requirement for electric vehicle market, it is appropriate to lower the cost and improve the energy density of lithium-ion batteries by adopting the Co-free and Ni-rich layered cathodes.However, t...Owing to the further requirement for electric vehicle market, it is appropriate to lower the cost and improve the energy density of lithium-ion batteries by adopting the Co-free and Ni-rich layered cathodes.However, their practical application is severely limited by structural instability and slow kinetics. Herein,ultrahigh-nickel cobalt-free LiNi_(0.9)Mn_(0.1)O_(2) cathode is elaborate designed via in-situ trace substitution of tungsten by a wet co-precipitation method following by high-temperature sintering. It is revealed that the in-situ doping strategy of high valence W^(6+) can effectively improve the structure stability by reducing irreversible phase transition and suppressing the formation of microcracks. Moreover, the transformed fine particles determined by W-doping can facilitate the kinetic characteristics by shortening Li^(+) diffusion paths. As expected, 0.3 mol% W-doped LiNi_(0.9)Mn_(0.1)O_(2) cathode exhibits a high specific capacity of 143.5 mAh/g after 200 cycles at high rate of 5 C in the wide potential range of 2.8-4.5 V, representing a potential next-generation cathode with low-cost, high energy-density and fast-charging capabilities.展开更多
Potassium-ion batteries(PlBs)are considered as the promising alternative of lithium-ion batteries,due to their abundance natural resources,high cost-effectiveness,and similar working principle.With the development of ...Potassium-ion batteries(PlBs)are considered as the promising alternative of lithium-ion batteries,due to their abundance natural resources,high cost-effectiveness,and similar working principle.With the development of PIBs,due to the larger ionic radius of potassium compared to that of lithium,the urgent demand of suitable anode materials with steady structure and fast carrier diffusion is of primary importance.展开更多
Benefited from its high process feasibility and controllable costs,binary-metal layered structured LiNi_(0.8)Mn_(0.2)O_(2)(NM)can effectively alleviate the cobalt supply crisis under the surge of global electric vehic...Benefited from its high process feasibility and controllable costs,binary-metal layered structured LiNi_(0.8)Mn_(0.2)O_(2)(NM)can effectively alleviate the cobalt supply crisis under the surge of global electric vehicles(EVs)sales,which is considered as the most promising nextgeneration cathode material for lithium-ion batteries(LIBs).However,the lack of deep understanding on the failure mechanism of NM has seriously hindered its application,especially under the harsh condition of high-voltage without sacrifices of reversible capacity.Herein,singlecrystal LiNi_(0.8)Mn_(0.2)O_(2) is selected and compared with traditional LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)(NCM),mainly focusing on the failure mechanism of Cofree cathode and illuminating the significant effect of Co element on the Li/Ni antisite defect and dynamic characteristic.Specifically,the presence of high Li/Ni antisite defect in NM cathode easily results in the extremely dramatic H2/H3 phase transition,which exacerbates the distortion of the lattice,mechanical strain changes and exhibits poor electrochemical performance,especially under the high cutoff voltage.Furthermore,the reaction kinetic of NM is impaired due to the absence of Co element,especially at the single-crystal architecture.Whereas,the negative influence of Li/Ni antisite defect is controllable at low current densities,owing to the attenuated polarization.Notably,Co-free NM can exhibit better safety performance than that of NCM cathode.These findings are beneficial for understanding the fundamental reaction mechanism of single-crystal Ni-rich Co-free cathode materials,providing new insights and great encouragements to design and develop the next generation of LIBs with low-cost and high-safety performances.展开更多
LiNi_(0.5)Co_(0.2)Mn_(0.3)O_(2) is extensively researched as one of the most widely used commercially materials for Li-ion batteries at present.However,the poor high-voltage performance(≥4.3 V)with low reversible cap...LiNi_(0.5)Co_(0.2)Mn_(0.3)O_(2) is extensively researched as one of the most widely used commercially materials for Li-ion batteries at present.However,the poor high-voltage performance(≥4.3 V)with low reversible capacity limits its replacement for LiCoO_(2) in high-end digital field.Herein,three-in-one modification,Na-doping and Al_(2)O_(3)@Li_(3)BO_(3) dual-coating simultaneously,is explored for single-crystalline LiNi_(0.5)Co_(0.2)Mn_(0.3)O_(2)(N-NCM@AB),which exhibits excellent high-voltage performance.N-NCM@AB displays a discharge-specific capacity of 201.8 mAh g^(−1) at 0.2 C with a high upper voltage of 4.6 V and maintains 158.9 mAh g^(−1) discharge capacity at 1 C over 200 cycles with the corresponding capacity retention of 87.8%.Remarkably,the N-NCM@AB||graphite pouch-type full cell retains 81.2% of its initial capacity with high working voltage of 4.4 V over 1600 cycles.More importantly,the fundamental understandings of three-in-one modification on surface morphology,crystal structure,and phase transformation of N-NCM@AB are clearly revealed.The Na+doped into the Li–O slab can enhance the bond energy,stabilize the crystal structure,and facilitate Li+transport.Additionally,the interior surface layer of Li^(+)-ions conductor Li_(3)BO_(3) relieves the charge transfer resistance with surface coating,whereas the outer surface Al_(2)O_(3) coating layer is beneficial for reducing the active materials loss and alleviating the electrode/electrolyte parasite reaction.This three-in-one strategy provides a reference for the further research on the performance attenuation mechanism of NCM,paving a new avenue to boost the high-voltage performance of NCM cathode in Li-ion batteries.展开更多
The intrinsic poor electrical conductivity,severe dissolution of K x S y intermediates,and inferior conversion reaction reversibility extremely impede the practical application of the transition-metal chalcogenides(TM...The intrinsic poor electrical conductivity,severe dissolution of K x S y intermediates,and inferior conversion reaction reversibility extremely impede the practical application of the transition-metal chalcogenides(TMDs)anode for potassium-ion batteries(PIBs).Herein,a rationally designed Cu_(9)S_(5)/MoS_(2)/C heterostruc-ture hollow nanocage was synthesized with assistance from metal-organic frameworks(MOFs)precursor.During the K-storage process,the homogeneously distributed the sulfiphilic nature of Cu 0 reaction prod-uct could act as a dual-functional catalyst,not only facilitating the rapid charge transfer but also effec-tively anchoring(K x S y)polysulfides,thus boosting K-storage reactions reversibility during the conversion reaction process.When applied as an anode for PIBs,the as-prepared heterostructure exhibits excellent reversible capacity and long cycle lifespan(350.5 mAh g^(-1)at 0.1 A g^(-1)and 0.04%per cycle capacity de-cay at 1 A g^(-1)after 1000 cycles).Additionally,the potassium storage mechanism is distinctly revealed by in-situ characterizations.The nanoarchitecture designing strategy for the advanced electrode in this work could provide vital guidance for relevant energy storage materials.展开更多
Generally,layered Ni-rich cathode materials exhibit the morphology of polycrystalline secondary sphere composed of numerous primary particles.While the arrangement of primary particles plays a very important role in t...Generally,layered Ni-rich cathode materials exhibit the morphology of polycrystalline secondary sphere composed of numerous primary particles.While the arrangement of primary particles plays a very important role in the properties of Ni-rich cathodes.The disordered particle arrangement is harmful to the cyclic performance and structural stability,yet the fundamental understanding of disordered structure on the structural degradation behavior is unclarified.Herein,we have designed three kinds of LiNi_(0.83)Co_(0.06)Mn_(0.11)O_(2) cathode materials with different primary particle orientations by regulating the precursor coprecipitation process.Combining finite element simulation and in-situ characterization,the Li^(+)transport and structure evolution behaviors of different materials are unraveled.Specifically,the smooth Li^(+)diffusion minimizes the reaction heterogeneity,homogenizes the phase transition within grains,and mitigates the anisotropic microstructural change,thereby modulating the crack evolution behavior.Meanwhile,the optimized structure evolution ensures radial tight junctions of the primary particles,enabling enhanced Li^(+)diffusion during dynamic processes.Closed-loop bidirectional enhancement mechanism becomes critical for grain orientation regulation to stabilize the cyclic performance.This precursor engineering with particle orientation regulation provides the useful guidance for the structural design and feature enhancement of Ni-rich layered cathodes.展开更多
Advancing high-voltage stability of layered sodium-ion oxides represents a pivotal avenue for their progress in energy storage applications.Despite this,a comprehensive understanding of the mechanisms underpinning the...Advancing high-voltage stability of layered sodium-ion oxides represents a pivotal avenue for their progress in energy storage applications.Despite this,a comprehensive understanding of the mechanisms underpinning their structural deterioration at elevated voltages remains insufficiently explored.In this study,we unveil a layer delamination phenomenon of Na_(0.67)Ni_(0.3)Mn_(0.7)O_(2)(NNM)within the 2.0-4.3 V voltage,attributed to considerable volumetric fluctuations along the c-axis and lattice oxygen reactions induced by the simultaneous Ni^(3+)/Ni^(4+)and anion redox reactions.By introducing Mg doping to diminished Ni-O antibonding,the anion oxidation-reduction reactions are effectively mitigated,and the structural integrity of the P2 phase remains firmly intact,safeguarding active sites and precluding the formation of novel interfaces.The Na_(0.67)Mg_(0.05)Ni_(0.25)Mn_(0.7)O_(2)(NMNM-5)exhibits a specific capacity of100.7 mA h g^(-1),signifying an 83%improvement compared to the NNM material within the voltage of2.0-4.3 V.This investigation underscores the intricate interplay between high-voltage stability and structural degradation mechanisms in layered sodium-ion oxides.展开更多
Various and critical electrocatalytic processes are involved during the redox reactions in the Li-S batteries,which extremely depend on the surface structure and chemical state.Recently,single-atom concept unlocks a r...Various and critical electrocatalytic processes are involved during the redox reactions in the Li-S batteries,which extremely depend on the surface structure and chemical state.Recently,single-atom concept unlocks a route to maximize the use of surface-active atoms,however,further increasing the density of active site is still strictly limited by the inherent structure that single-atoms are only highly-dispersed on substrate.Herein,we provide a viewpoint that an elaborate facet design with singlecrystalline structure engineering can harvest high-density surface active sites,which can significantly boost the electrocatalyst performance for excellent Li-S batteries.Specifically,the single-crystal CoSe_(2)(scCS)exhibits three-types of terminated(011)facet,efficiently obtaining the surface with a high-rich Co^(3+)–Se bond termination,in contrast with lots of surface grain boundaries and dangling bonds in polycrystalline CoSe_(2).Surprisingly,the surface active sites concentration can reach more than 69%.As anticipated,it can provide high-density and high-efficient active sites,enormously suppressing the shuttle effect and improving the reaction kinetics via accelerating the conversion and deposition of polysulfides and Li2S.This surface lattice strategy with element terminated mode is a promising approach for designing electrocatalyst effect-based energy system,not merely for Li-S batteries.展开更多
Molybdenum disulfide (MoS_(2)) has received enormous attentions in the electrochemical energy storage due to its unique two-dimensional layered structure and relatively high reversible capacity. However, the applicati...Molybdenum disulfide (MoS_(2)) has received enormous attentions in the electrochemical energy storage due to its unique two-dimensional layered structure and relatively high reversible capacity. However, the application of MoS_(2) in potassium-ion batteries (PIBs) is restricted by poor rate capability and cyclability, which are associated with the sluggish reaction kinetics and the huge volume expansion during K+ intercalation. Herein, we propose a two-dimensional (2D) space confined strategy to construct van der Waals heterostructure for superior PIB anode, in which the MoS_(2) nanosheets can be well dispersed on reduced graphene oxide nanosheets by leveraging the confinement effect within the graphene layers and amorphous carbon. The strong synergistic effects in 2D van der Waals heterostructure can extremely promote the electron transportation and ions diffusion during K+ insertion/extraction. More significantly, the 2D space-confinement effect and van der Waals force inhibit polysulfide conversion product dissolution into the electrolyte, which significantly strengthens the structural durability during the long-term cycling process. As anticipated, the as-synthesized the “face-to-face” C/MoS_(2)/G anode delivers remarkable K-storage performance, especially for high reversible capacity (362.5 mAh·g^(-1) at 0.1 A·g^(-1)), excellent rate capability (195.4 mAh·g^(-1) at 10 Ag^(-1)) and superior ultrahigh-rate long-cycling stability (126.4 mAh·g^(-1) after 4000 cycles at high rate of 5 A·g^(-1)). This work presents a promise strategy of structure designing and composition optimization for 2D layered materials in advanced energy storage application.展开更多
The spent lithium-ion batteries recovery has been brought into focus widely for its environmental imperatives and potential profits from the metal components,such as lithium,cobalt,nickel and manganese.However,the wea...The spent lithium-ion batteries recovery has been brought into focus widely for its environmental imperatives and potential profits from the metal components,such as lithium,cobalt,nickel and manganese.However,the weaker pollution and fewer profits of LiMn_(2)O_(4) cathode dispel the enthusiasm and responsibility of industry companies.Thus,a simplified and efncient method to regenerate the sodium-ion cathode materials and separate Li from spent LiMn_(2)O_(4) materials for the profit improvement is proposed.In detail,adjusting the parameters of carbothermal reduction process appropriately,the LiMn_(2)O_(4) spinel structure is destroyed within a short period time and transformed into simple metal oxide.As anticipated,nearly 95 wt.%lithium can be obtained and recovered during the water leaching,while 99 wt.%of manganese can be extracted in acid solution.Noted that the leaching residue can return to the carbothermic reduction,leading to a closed-loop economic recycling process.The regenerated Na_(0.67)Ni_(0.3)Mn_(0.7)O_(2) cathode displays excellent electrochemical performance with superior cycling stability(the initial capacity reaches 95.9 mAh·g^(-1),and the retention rate reached 98.3%after 100 cycles at 1 C).The delicate strategy of sodium-ion cathode material regenerated from spent LiMn_(2)O_(4) aims to realize lithium separation and material utilization of manganese simultaneously,providing the instructive suggestion to rise up the recycling profits of spent batteries.展开更多
基金supported by the National Natural Science Foundation of China(No.52122407,No.52174285,52404317)the Science and Technology Innovation Program of Hunan Province(No.2022RC3048).
文摘LiNiO_(2)(LNO)is one of the most promising cathode materials for lithium-ion batteries.Tungsten element in enhancing the stability of LNO has been researched extensively.However,the understanding of the specific doping process and existing form of W are still not perfect.This study proposes a lithium-induced grain boundary phase W doping mechanism.The results demonstrate that the introduced W atomsfirst react with the lithium source to generate a Li–W–O phase at the grain boundary of primary particles.With the increase of lithium ratio,W atoms gradually diffuse from the grain boundary phase to the interior layered structure to achieve W doping.The feasibility of grain boundary phase doping is verified byfirst principles calculation.Furthermore,it is found that the Li2WO4 grain boundary phase is an excellent lithium ion conductor,which can protect the cathode surface and improve the rate performance.The doped W can alleviate the harmful H2↔H3 phase transition,thereby inhibiting the generation of microcracks,and improving the electrochemical performance.Consequently,the 0.3 wt%W-doped sample provides a significant improved capacity retention of 88.5%compared with the pristine LNO(80.7%)after 100 cycles at 2.8–4.3 V under 1C.
基金the financial support from the Guangxi Natural Science Foundation(grant no.2021GXNSFDA075012,2023GXNSFGA026002)National Natural Science Foundation of China(52104298,22075073,52362027,52462029)Fundamental Research Funds for the Central Universities(531107051077).
文摘Stress accumulation is a key factor leading to sodium storage performance deterioration for NiSe_(2)-based anodes.Therefore,inhibiting the concentrated local stress during the sodiataion/desodiation process is crucial for acquiring stable NiSe2-based materials for sodium-ion batteries(SIBs),Herein,a stress dissipation strategy driven by architecture engineering is proposed,which can achieve ultrafast and ultralong sodium storage properties.Different from the conventional sphere-like or rod-like architecture,the three-dimensional(3D)flower-like NiSe_(2)@C composite is delicately designed and assembled with onedimensional nanorods and carbon framework.More importantly,the fundamental mechanism of improved structure stability is unveiled by simulations and experimental results simultaneously.It demonstrates that this designed multidimensional flower-like architecture with dispersed nanorods can balance the structural mismatch,avoid concentrated local strain,and relax the internal stress,mainly induced by the unavoidable volume variation during the repeated conversion processes.Moreover,it can provide more Na^(+)-storage sites and multi-directional migration pathways,leading to a fast Na^(+)-migration channel with boosted reaction kinetic.As expected,it delivers superior rate performance(441 mA h g^(-1)at 5.0 A g^(-1))and long cycling stability(563 mA h g^(-1)at 1.0 A g^(-1)over 1000 cycles)for SIBs.This work provides useful insights for designing high-performance conversion-based anode materials for SIBs.
基金supported by the National Natural Science Foundation of China(No.51072130,51502045 and 21905202)the Australian Research Council(ARC)through Discovery Project(No.DP200100365)the Discovery Early Career Researcher Award(DECRA,No.DE170100871)program。
文摘Aqueous zinc-ion batteries(ZIBs)are receiving a continuously increasing attention for mobile devices,especially for the flexible and wearable electronics,due to their non-toxicity,non-flammability,and low-cost features.Despite the significant progress in achieving higher capacities for electrode materials of ZIBs,to endow them with high flexibility and economic feasibility is,however,still a significant challenge remaining unsolved.Herein,we present a highly flexible composite film composed of carbon nanotube film and V_(2)O_(5)(CNTF@V_(2)O_(5))with high strength and high conductivity,which is prepared by simply impregnating a porous CNT film with an aqueous V_(2)O_(5)sol under vacuum.For this material,intimate incorporation between V_(2)O_(5)and CNTs has been achieved,successfully integrating the high zinc ion storage capability with high mechanical flexibility.As a result,this CNTF@V_(2)O_(5)film delivers a high capacity of 356.6 m Ah g^(-1)at 0.4 A g^(-1)and excellent cycling stability with 80.1%capacity retention after 500 cycles at 2.0 A g^(-1).The novel strategy and the outstanding battery performance presented in this work should shed light on the development of high-performance and flexible ZIBs.
基金This work was supported by National Natural Science Foundation of China(51902347,51822812,51772334,51778627).
文摘Along with the extensive application of energy storage devices,the spent lithium-ion batteries(LIBs)are unquestionably classified into the secondary resources due to its high content of several valuable metals.However,current recycling methods have the main drawback to their tedious process,especially the purification and separation process.Herein,we propose a simplified process to recycle both cathode(LiCoO_(2))and anode(graphite)in the spent LIBs and regenerate newly high-performance anode material,CoO/CoFe2O4/expanded graphite(EG).This process not only has the advantages of succinct procedure and easy control of reaction conditions,but also effectively separates and recycles lithium from transition metals.The 98.43%of lithium is recovered from leachate when the solid product CoO/CoFe2O4/EG is synthesized as anode material for LIBs.And the product exhibits improved cyclic stability(890 mAh g^(-1) at 1 A g^(-1) after 700 cycles)and superior rate capability(208 mAh g^(-1) at 5 A g^(-1)).The merit of this delicate recycling design can be summarized as three aspects:the utilization of Fe impurity in waste LiCoO_(2),the transformation of waste graphite to EG,and the regeneration of anode material.This approach properly recycles the valuable components of spent LIBs,which introduces an insight into the future recycling.
基金financially supported by the National Natural Science Foundation of China(Nos.51822812,51778627)the Fundamental Research Funds for the Central Universities of Central South University(No.2020zzts474)。
文摘In this paper,the ammonia leaching process and high-energy ball milling method were adapted to recover spent LiCoO_(2) material.The ammonia reduction leaching mechanism of LiCoO_(2) material in the ammonia-sodium sulfite-ammonium chloride system was elucidated.Compared with untreated LiCoO_(2) material,the leaching equilibrium time of LiCoO_(2) after ball-milled for 5 h was reduced from 48 h to 4 h,and the leaching efficiency of lithium and cobalt was improved from 69.86%and 70.80%to 89.86%and98.22%,respectively.Importantly,the apparent activation energy and leaching kinetic equation of the reaction was calculated by the shrinking core reaction model,indicating that the reaction was controlled by the chemical reaction.
基金financial support from the National Natural Science Foundation of China (Nos. 51908555, 52070194)。
文摘Owing to the further requirement for electric vehicle market, it is appropriate to lower the cost and improve the energy density of lithium-ion batteries by adopting the Co-free and Ni-rich layered cathodes.However, their practical application is severely limited by structural instability and slow kinetics. Herein,ultrahigh-nickel cobalt-free LiNi_(0.9)Mn_(0.1)O_(2) cathode is elaborate designed via in-situ trace substitution of tungsten by a wet co-precipitation method following by high-temperature sintering. It is revealed that the in-situ doping strategy of high valence W^(6+) can effectively improve the structure stability by reducing irreversible phase transition and suppressing the formation of microcracks. Moreover, the transformed fine particles determined by W-doping can facilitate the kinetic characteristics by shortening Li^(+) diffusion paths. As expected, 0.3 mol% W-doped LiNi_(0.9)Mn_(0.1)O_(2) cathode exhibits a high specific capacity of 143.5 mAh/g after 200 cycles at high rate of 5 C in the wide potential range of 2.8-4.5 V, representing a potential next-generation cathode with low-cost, high energy-density and fast-charging capabilities.
基金financially supported by the National Natural Science Foundation of China (Nos.52070194, 52073309 and 51902347)the Natural Science Foundation of Hunan Province (No.2020JJ5741)
文摘Potassium-ion batteries(PlBs)are considered as the promising alternative of lithium-ion batteries,due to their abundance natural resources,high cost-effectiveness,and similar working principle.With the development of PIBs,due to the larger ionic radius of potassium compared to that of lithium,the urgent demand of suitable anode materials with steady structure and fast carrier diffusion is of primary importance.
基金the National Natural Science Foundation of China(52070194,52073309,51902347,51908555)Natural Science Foundation of Hunan Province(2022JJ20069,2020JJ5741).
文摘Benefited from its high process feasibility and controllable costs,binary-metal layered structured LiNi_(0.8)Mn_(0.2)O_(2)(NM)can effectively alleviate the cobalt supply crisis under the surge of global electric vehicles(EVs)sales,which is considered as the most promising nextgeneration cathode material for lithium-ion batteries(LIBs).However,the lack of deep understanding on the failure mechanism of NM has seriously hindered its application,especially under the harsh condition of high-voltage without sacrifices of reversible capacity.Herein,singlecrystal LiNi_(0.8)Mn_(0.2)O_(2) is selected and compared with traditional LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)(NCM),mainly focusing on the failure mechanism of Cofree cathode and illuminating the significant effect of Co element on the Li/Ni antisite defect and dynamic characteristic.Specifically,the presence of high Li/Ni antisite defect in NM cathode easily results in the extremely dramatic H2/H3 phase transition,which exacerbates the distortion of the lattice,mechanical strain changes and exhibits poor electrochemical performance,especially under the high cutoff voltage.Furthermore,the reaction kinetic of NM is impaired due to the absence of Co element,especially at the single-crystal architecture.Whereas,the negative influence of Li/Ni antisite defect is controllable at low current densities,owing to the attenuated polarization.Notably,Co-free NM can exhibit better safety performance than that of NCM cathode.These findings are beneficial for understanding the fundamental reaction mechanism of single-crystal Ni-rich Co-free cathode materials,providing new insights and great encouragements to design and develop the next generation of LIBs with low-cost and high-safety performances.
基金We gratefully acknowledge the financial support from the National Natural Science Foundation of China(52070194,51902347,51908555,and 51822812)Natural Science Foundation of Hunan Province(2020JJ5741)the Graduate Innovation Project of Central South University(2020zzts093).
文摘LiNi_(0.5)Co_(0.2)Mn_(0.3)O_(2) is extensively researched as one of the most widely used commercially materials for Li-ion batteries at present.However,the poor high-voltage performance(≥4.3 V)with low reversible capacity limits its replacement for LiCoO_(2) in high-end digital field.Herein,three-in-one modification,Na-doping and Al_(2)O_(3)@Li_(3)BO_(3) dual-coating simultaneously,is explored for single-crystalline LiNi_(0.5)Co_(0.2)Mn_(0.3)O_(2)(N-NCM@AB),which exhibits excellent high-voltage performance.N-NCM@AB displays a discharge-specific capacity of 201.8 mAh g^(−1) at 0.2 C with a high upper voltage of 4.6 V and maintains 158.9 mAh g^(−1) discharge capacity at 1 C over 200 cycles with the corresponding capacity retention of 87.8%.Remarkably,the N-NCM@AB||graphite pouch-type full cell retains 81.2% of its initial capacity with high working voltage of 4.4 V over 1600 cycles.More importantly,the fundamental understandings of three-in-one modification on surface morphology,crystal structure,and phase transformation of N-NCM@AB are clearly revealed.The Na+doped into the Li–O slab can enhance the bond energy,stabilize the crystal structure,and facilitate Li+transport.Additionally,the interior surface layer of Li^(+)-ions conductor Li_(3)BO_(3) relieves the charge transfer resistance with surface coating,whereas the outer surface Al_(2)O_(3) coating layer is beneficial for reducing the active materials loss and alleviating the electrode/electrolyte parasite reaction.This three-in-one strategy provides a reference for the further research on the performance attenuation mechanism of NCM,paving a new avenue to boost the high-voltage performance of NCM cathode in Li-ion batteries.
基金financially supported by the National Natural Science Foundation of China (Nos.52070194,52073309,51902347,and 51908555)the Natural Science Foundation of Hunan Province (Nos.2022JJ20069 and 2020JJ5741).
文摘The intrinsic poor electrical conductivity,severe dissolution of K x S y intermediates,and inferior conversion reaction reversibility extremely impede the practical application of the transition-metal chalcogenides(TMDs)anode for potassium-ion batteries(PIBs).Herein,a rationally designed Cu_(9)S_(5)/MoS_(2)/C heterostruc-ture hollow nanocage was synthesized with assistance from metal-organic frameworks(MOFs)precursor.During the K-storage process,the homogeneously distributed the sulfiphilic nature of Cu 0 reaction prod-uct could act as a dual-functional catalyst,not only facilitating the rapid charge transfer but also effec-tively anchoring(K x S y)polysulfides,thus boosting K-storage reactions reversibility during the conversion reaction process.When applied as an anode for PIBs,the as-prepared heterostructure exhibits excellent reversible capacity and long cycle lifespan(350.5 mAh g^(-1)at 0.1 A g^(-1)and 0.04%per cycle capacity de-cay at 1 A g^(-1)after 1000 cycles).Additionally,the potassium storage mechanism is distinctly revealed by in-situ characterizations.The nanoarchitecture designing strategy for the advanced electrode in this work could provide vital guidance for relevant energy storage materials.
基金supported by National Natural Science Foundation of China (52070194,52073309)Natural Science Foundation of Hunan Province (2022JJ20069)。
文摘Generally,layered Ni-rich cathode materials exhibit the morphology of polycrystalline secondary sphere composed of numerous primary particles.While the arrangement of primary particles plays a very important role in the properties of Ni-rich cathodes.The disordered particle arrangement is harmful to the cyclic performance and structural stability,yet the fundamental understanding of disordered structure on the structural degradation behavior is unclarified.Herein,we have designed three kinds of LiNi_(0.83)Co_(0.06)Mn_(0.11)O_(2) cathode materials with different primary particle orientations by regulating the precursor coprecipitation process.Combining finite element simulation and in-situ characterization,the Li^(+)transport and structure evolution behaviors of different materials are unraveled.Specifically,the smooth Li^(+)diffusion minimizes the reaction heterogeneity,homogenizes the phase transition within grains,and mitigates the anisotropic microstructural change,thereby modulating the crack evolution behavior.Meanwhile,the optimized structure evolution ensures radial tight junctions of the primary particles,enabling enhanced Li^(+)diffusion during dynamic processes.Closed-loop bidirectional enhancement mechanism becomes critical for grain orientation regulation to stabilize the cyclic performance.This precursor engineering with particle orientation regulation provides the useful guidance for the structural design and feature enhancement of Ni-rich layered cathodes.
基金the financial support from the National Natural Science Foundation of China(52202338)。
文摘Advancing high-voltage stability of layered sodium-ion oxides represents a pivotal avenue for their progress in energy storage applications.Despite this,a comprehensive understanding of the mechanisms underpinning their structural deterioration at elevated voltages remains insufficiently explored.In this study,we unveil a layer delamination phenomenon of Na_(0.67)Ni_(0.3)Mn_(0.7)O_(2)(NNM)within the 2.0-4.3 V voltage,attributed to considerable volumetric fluctuations along the c-axis and lattice oxygen reactions induced by the simultaneous Ni^(3+)/Ni^(4+)and anion redox reactions.By introducing Mg doping to diminished Ni-O antibonding,the anion oxidation-reduction reactions are effectively mitigated,and the structural integrity of the P2 phase remains firmly intact,safeguarding active sites and precluding the formation of novel interfaces.The Na_(0.67)Mg_(0.05)Ni_(0.25)Mn_(0.7)O_(2)(NMNM-5)exhibits a specific capacity of100.7 mA h g^(-1),signifying an 83%improvement compared to the NNM material within the voltage of2.0-4.3 V.This investigation underscores the intricate interplay between high-voltage stability and structural degradation mechanisms in layered sodium-ion oxides.
基金National Natural Science Foundation of China(Nos.52070194,52073309,51902347,51932003,51872115,and 22109135)Science and Technology Development Project of Jilin Province(Nos.YDZJ202101ZYTS165,20210506034ZP,and 20210509051RQ).
文摘Various and critical electrocatalytic processes are involved during the redox reactions in the Li-S batteries,which extremely depend on the surface structure and chemical state.Recently,single-atom concept unlocks a route to maximize the use of surface-active atoms,however,further increasing the density of active site is still strictly limited by the inherent structure that single-atoms are only highly-dispersed on substrate.Herein,we provide a viewpoint that an elaborate facet design with singlecrystalline structure engineering can harvest high-density surface active sites,which can significantly boost the electrocatalyst performance for excellent Li-S batteries.Specifically,the single-crystal CoSe_(2)(scCS)exhibits three-types of terminated(011)facet,efficiently obtaining the surface with a high-rich Co^(3+)–Se bond termination,in contrast with lots of surface grain boundaries and dangling bonds in polycrystalline CoSe_(2).Surprisingly,the surface active sites concentration can reach more than 69%.As anticipated,it can provide high-density and high-efficient active sites,enormously suppressing the shuttle effect and improving the reaction kinetics via accelerating the conversion and deposition of polysulfides and Li2S.This surface lattice strategy with element terminated mode is a promising approach for designing electrocatalyst effect-based energy system,not merely for Li-S batteries.
基金This work was financially supported by the National Natural Science Foundation of China(Nos.51902347,51822812,51772334,and 51778627)Natural Science Foundation of Hunan Province(No.2020JJ5741).
文摘Molybdenum disulfide (MoS_(2)) has received enormous attentions in the electrochemical energy storage due to its unique two-dimensional layered structure and relatively high reversible capacity. However, the application of MoS_(2) in potassium-ion batteries (PIBs) is restricted by poor rate capability and cyclability, which are associated with the sluggish reaction kinetics and the huge volume expansion during K+ intercalation. Herein, we propose a two-dimensional (2D) space confined strategy to construct van der Waals heterostructure for superior PIB anode, in which the MoS_(2) nanosheets can be well dispersed on reduced graphene oxide nanosheets by leveraging the confinement effect within the graphene layers and amorphous carbon. The strong synergistic effects in 2D van der Waals heterostructure can extremely promote the electron transportation and ions diffusion during K+ insertion/extraction. More significantly, the 2D space-confinement effect and van der Waals force inhibit polysulfide conversion product dissolution into the electrolyte, which significantly strengthens the structural durability during the long-term cycling process. As anticipated, the as-synthesized the “face-to-face” C/MoS_(2)/G anode delivers remarkable K-storage performance, especially for high reversible capacity (362.5 mAh·g^(-1) at 0.1 A·g^(-1)), excellent rate capability (195.4 mAh·g^(-1) at 10 Ag^(-1)) and superior ultrahigh-rate long-cycling stability (126.4 mAh·g^(-1) after 4000 cycles at high rate of 5 A·g^(-1)). This work presents a promise strategy of structure designing and composition optimization for 2D layered materials in advanced energy storage application.
基金supported by the National Natural Science Foundation of China(52070194,52073309)the Natural Science Foundation of Hunan Province(2022JJ20069)。
文摘The spent lithium-ion batteries recovery has been brought into focus widely for its environmental imperatives and potential profits from the metal components,such as lithium,cobalt,nickel and manganese.However,the weaker pollution and fewer profits of LiMn_(2)O_(4) cathode dispel the enthusiasm and responsibility of industry companies.Thus,a simplified and efncient method to regenerate the sodium-ion cathode materials and separate Li from spent LiMn_(2)O_(4) materials for the profit improvement is proposed.In detail,adjusting the parameters of carbothermal reduction process appropriately,the LiMn_(2)O_(4) spinel structure is destroyed within a short period time and transformed into simple metal oxide.As anticipated,nearly 95 wt.%lithium can be obtained and recovered during the water leaching,while 99 wt.%of manganese can be extracted in acid solution.Noted that the leaching residue can return to the carbothermic reduction,leading to a closed-loop economic recycling process.The regenerated Na_(0.67)Ni_(0.3)Mn_(0.7)O_(2) cathode displays excellent electrochemical performance with superior cycling stability(the initial capacity reaches 95.9 mAh·g^(-1),and the retention rate reached 98.3%after 100 cycles at 1 C).The delicate strategy of sodium-ion cathode material regenerated from spent LiMn_(2)O_(4) aims to realize lithium separation and material utilization of manganese simultaneously,providing the instructive suggestion to rise up the recycling profits of spent batteries.
