In this work, the electrochemical performance of LiNi0.8Co0.1Mn0.1O2(NCM811) has been investigated after cycling with various upper cutoff voltages. Noteworthily, electrochemical impedance of NCM811 declined with the ...In this work, the electrochemical performance of LiNi0.8Co0.1Mn0.1O2(NCM811) has been investigated after cycling with various upper cutoff voltages. Noteworthily, electrochemical impedance of NCM811 declined with the increasing cycle number to high voltages. It was found that the decline of charge transfer impedance could be related to the structural and compositional change of cathode electrolyte interphase(CEI) of NCM811 when charging to high voltages, based on the characterization of electrochemical impedance spectroscopy(EIS), X-ray photoelectron spectroscopy(XPS) and transmission electron microscopy(TEM). The corresponding mechanism has also been proposed in this study. Specifically, due to the increasing roughness of cathode surface, the bottom of CEI film and cubic phase on cathode surface form a transition region mainly at high voltages, leading to the nonobvious boundary. This newly formed transition region at high voltages could promote the Li ion diffusion from electrolyte to cathode, then reducing charge transfer impedance. Additionally, the decrease of Li F on the surface of the cathode could also make a contribution to lower the interface impedance. This study delivers a different evolution of CEI on NCM811, and the impact of CEI evolution on electrochemical performance when charging to a high voltage.展开更多
With the advancement of secondary batteries,interfacial properties of electrode materials have been recognized as essential factors to their electrochemical performance.However,the majority of investigations are devot...With the advancement of secondary batteries,interfacial properties of electrode materials have been recognized as essential factors to their electrochemical performance.However,the majority of investigations are devoted into advanced electrode materials synthesis,while there is insufficient attention paid to regulate their interfaces.In this regard,the solid electrolyte interphase(SEI)at anode part has been studied for 40 years,already achieving remarkable outcomes on improving the stability of anode candidates.Unfortunately,the study on the cathode electrolyte interfaces(CEI)remains in infancy,which constitutes a potential restriction to the capacity contribution,stability and safety of cathodes.In fact,the native CEI generally possesses unfavorable characteristics against structural and compositional stability that requires demanding optimization strategies.Meanwhile,an in-depth understanding of the CEI is of great significance to guide the optimization principles in terms of composition,structure,growth mechanism,and electrochemical properties.In this literature,recent progress and advances of the CEI characterization methods and optimization protocols are summarized,and meanwhile the mutually-reinforced mechanisms between detection and modification are explained.The criteria and the potential development of the CEI characterization are proposed with insights of novel optimization directions.展开更多
Lithium-sulfur batteries(LSBs)are regarded as the most promising next-generation energy system due to their high theoretical energy density.However,LSBs suffer the“shuttle effect”if undergoing the solid-liquid-solid...Lithium-sulfur batteries(LSBs)are regarded as the most promising next-generation energy system due to their high theoretical energy density.However,LSBs suffer the“shuttle effect”if undergoing the solid-liquid-solid sulfur conversion process during cycling.Herein,we design a solvent-in-salt(SIS)electrolyte with co-solvent vinylene carbonate(VC)to synthesize an in situ dense cathode electrolyte interface(CEI)and successfully change sulfur conversion into a solid-solid way to avoid shuttle effect by separating the contact of sulfur and ether solvent.Dense CEI is formed at the beginning of first discharge by the combined action of SIS electrolyte and filmogen VC.Experiments and simulations show that SIS electrolyte controls the initial formed lithium polysulfides(LiPSs)to stay very closely on the cathode surface,and then converts them into a dense CEI film.As a result,Coulombic efficiency(above 99%)and cycling performance of LSBs are improved.Furthermore,the in situ dense CEI can nearly stop the self-discharge of LSBs,and enable the LSBs to work under a pretty lean electrolyte condition.展开更多
Li-rich layered oxide cathodes have received considerable attention because of the high operating potential and specific capacity. However, the structural instability and parasitic reactions at high potential cause se...Li-rich layered oxide cathodes have received considerable attention because of the high operating potential and specific capacity. However, the structural instability and parasitic reactions at high potential cause severe degradation of the electrochemical performance. In our studies, the cycling stability of Li_(1.14)Ni_(0.133)Co_(0.133)Mn_(0.544)O_(2) cathode is improved with LiPO_(2)F_(2) electrolyte additive. After 500 cycles, the capacity retention is increased from 53.6% to 85% at 3 C by LiPO_(2)F_(2) modification. This performance is mainly attributed to the enhanced interfacial stability of the Li-rich cathode. Based on systematic characterization, LiPO_(2)F_(2) additive was found to promote a stable interface film on the cathode surface during the cycling and mitigates the interfacial side reactions. This study provides new insights for improving high-potential Li-rich layered oxide batteries.展开更多
With the continuous advancement of industrialization,sodium-ion batteries(SIBs)need to operate in various challenging circumstances,particularly in extremely cold conditions.However,at ultra-low tem-peratures,the redu...With the continuous advancement of industrialization,sodium-ion batteries(SIBs)need to operate in various challenging circumstances,particularly in extremely cold conditions.However,at ultra-low tem-peratures,the reduced ionic conductivity and sluggish Na+migration of commonly carbonate-based elec-trolytes will inevitably lead to a sharp decrease in the capacity of SIBs.Herein,we design a carboxylate ester-based electrolyte with excellent ultra-low temperature performance by straightforward cosolvent strategy.Due to the low viscosity,melting point,and sufficient ionic conductivity of the designed elec-trolyte,the resulting Na||Na_(3)V_(2)(PO_(4))_(2)O_(2)F can achieve the capacity retention of 96%(100 cycles at 0.1 C)at-40℃ and can also operate stably even at-50℃.Besides,galvanostatic intermittent titration tech-nique(GITT),ex-situ X-ray photoelectron spectroscopy(XPS),and high-resolution transmission electron microscopy(TEM)tests are employed to analyze and confirm that the carboxylate ester-based electrolyte promotes robust and uniform cathode/electrolyte interface layer formation and accelerates ion diffusion kinetics,which collectively facilitates the better low-temperature performance.In addition,the assembled hard carbon||NVPOF full cells further prove the practicability of the carboxylate ester-based electrolyte at low-temperature,which delivers high discharge capacity of 108.4 and 73.0 mAh g^(-1) at-25 and-40℃.This work affords a new avenue for designing advanced low-temperature electrolytes for SIBs.展开更多
High-voltage sodium-ion batteries(SIBs)are emerging as promising candidates for large-scale energy storage systems due to their abundant sodium source and high energy density.However,the instability of the electrode e...High-voltage sodium-ion batteries(SIBs)are emerging as promising candidates for large-scale energy storage systems due to their abundant sodium source and high energy density.However,the instability of the electrode electrolyte interphase remains a critical barrier to the potential use of high-voltage SIBs.Herein,sodium difluorophosphate(NaDFP)and fluoroethylene carbonate(FEC)serve as functional electrolyte additives to stabilize the interface of the high-voltage cathode.The oxidative competition between FEC and NaDFP facilitates the robust formation of the cathode-electrolyte interface(CEI)layer,enriched with inorganic components such as NaF/NaPO_(x)F_(y).The highly conductive NaF/NaPO_(x)F_(y)and inorganics provide fast ion transport pathways and mechanical strength,thereby mitigating the decomposition of carbonates and NaPF_(6).The half-cell equipped with BE 2 F+0.5 DFP demonstrates 93.9%capacity retention at 4.3 V across 600 cycles,showcasing excellent cycling capability.Full HC||NVOPF cells exhibit sustained performance with 91.69%capacity retention and a capacity of 91.57 mA·h/g over 1000 cycles at a 5 C rate.This study is poised to garner increased scholarly interest in the domain of rational electrolyte formulation for practical applications.展开更多
All-solid-state batteries potentially exhibit high specific energy and high safety,which is one of the development directions for nextgeneration lithium-ion batteries.The compatibility of all-solid composite electrode...All-solid-state batteries potentially exhibit high specific energy and high safety,which is one of the development directions for nextgeneration lithium-ion batteries.The compatibility of all-solid composite electrodes with high-nickel layered cathodes and inorganic solid electrolytes is one of the important problems to be solved.In addition,the interface and mechanical problems of high-nickel layered cathodes and inorganic solid electrolyte composite electrodes have not been thoroughly addressed.In this paper,the possible interface and mechanical problems in the preparation of high-nickel layered cathodes and inorganic solid electrolytes and their interface reaction during charge–discharge and cycling are reviewed.The mechanical contact problems from phenomena to internal causes are also analyzed.Uniform contact between the high-nickel cathode and solid electrolyte in space and the ionic conductivity of the solid electrolyte are the prerequisites for the good performance of a high-nickel layered cathode.The interface reaction and contact loss between the high-nickel layered cathode and solid electrolyte in the composite electrode directly affect the passage of ions and electrons into the active material.The buffer layer constructed on the high-nickel cathode surface can prevent direct contact between the active material and electrolyte and slow down their interface reaction.An appropriate protective layer can also slow down the interface contact loss by reducing the volume change of the high-nickel layered cathode during charge and discharge.Finally,the following recommendations are put forward to realize the development vision of high-nickel layered cathodes:(1)develop electrochemical systems for high-nickel layered cathodes and inorganic solid electrolytes;(2)elucidate the basic science of interface and electrode processes between high-nickel layered cathodes and inorganic solid electrolytes,clarify the mechanisms of the interfacial chemical and electrochemical reactions between the two materials,and address the intrinsic safety issues;(3)strengthen the development of research and engineering technologies and their preparation methods for composite electrodes with high-nickel layered cathodes and solid electrolytes and promote the industrialization of all-solid-state batteries.展开更多
Tris(trimethylsilyl)borate(TMSB) has been intensively studied to improve the performances of lithiumion batteries. However, it is still an interesting issue needed to be resolved for the research on the Li^(+) solvati...Tris(trimethylsilyl)borate(TMSB) has been intensively studied to improve the performances of lithiumion batteries. However, it is still an interesting issue needed to be resolved for the research on the Li^(+) solvation structure affected by TMSB additive. Herein, the electrochemical tests, quantum chemistry calculations, potential-resolved in-situ electrochemical impedance spectroscopy measurements and surface analyses were used to explore the effects of Li^(+) solvation structure with TMSB additive on the formation of the cathode electrolyte interface(CEI) film in LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)/Li half cells. The results reveal that the TMSB additive is easy to complex with Li^(+) ion, thus weaken the intermolecular force between Li^(+) ions and ethylene carbonate solvent, which is benefit for the cycle performance. Besides, the changed Li^(+) solvation structure results in a thin and dense CEI film containing compounds with Si–O and B–O bonds which is favorable to the transfer of Li^(+) ions. As a result, the performances of the LNCM811/Li half cells are effectively improved. This research provides a new idea to construct a high-performance CEI film by adjusting the Li^(+) solvation structures.展开更多
LiNi0.8Co0.1Mn0.1O_(2)(NCM811),a Ni-rich layered oxide,is a promising cathode material for high-energy density lithium-ion batteries(LIBs).However,its structural instability,caused by adverse phase transitions and con...LiNi0.8Co0.1Mn0.1O_(2)(NCM811),a Ni-rich layered oxide,is a promising cathode material for high-energy density lithium-ion batteries(LIBs).However,its structural instability,caused by adverse phase transitions and continuous oxygen release,as well as deteriorated interfacial stability due to excessive electrolyte oxidative decomposition,limits its widespread application.To address these issues,a new concept is proposed that surface targeted precise functionalization(STPF)of the NCM811 cathode using a synergistic slurry additive(SSA)approach.This approach involves coating the NCM811 particle surface with 3-aminopropyl dimethoxy methyl silane(3-ADMS),followed by the precise deposition of ascorbic acid via an acid-base interaction.The slurry additives induce the formation of an ultra-thin spinel surface layer and a stable cathode–electrolyte interface(CEI),which enhances the electrochemical kinetics and inhibits crack propagation.The STPF strategy implemented by the SSA approach significantly improves the cyclic stability and rate performance of the NCM811 cathode in both half-cell and full-cell configurations.This work establishes a promising strategy to enhance the structural stability and electrochemical performance of nickel-rich cathodes and provides a feasible route to promote practical applications of high-energy density lithium-ion battery technology.展开更多
The continuous lithium consumption during cycling severely reduces the energy density of the lithium battery,and thus,lithium compensation is essential.Herein,Li_(x)C_(6)O_(6)(x=2,4)was proposed as an air-stable high-...The continuous lithium consumption during cycling severely reduces the energy density of the lithium battery,and thus,lithium compensation is essential.Herein,Li_(x)C_(6)O_(6)(x=2,4)was proposed as an air-stable high-efficiency sacrificial additive in the cathode to compensate for the lost lithium ions in solid-state lithium batteries.Below a delithiation(oxidation)potential as low as 3.8 V,Li_(2)C_(6)O_(6) can release most of its Li^(+)ions(294.8 mAh g^(−1) in theory).Similarly,Li_(4)C_(6)O_(6) is also characteristic of low oxidation potential and high delithiation capacity(547.8 mAh g^(−1) in theory).The feasibility of using Li_(x)C_(6)O_(6) as the self-sacrificial additive in the cathode was verified with the marked increase of the initial charge capacity of the Li||LiFePO_(4)(half)cells and the initial discharge capacity of Cu||LiFePO_(4)(full)cells,and the improved electrolyte/cathode interface stability and interface contact,in the solid-state poly(ethylene oxide)-lithium bis(trifluoromethane)sulfonimide(PEO-LiTFSI)electrolyte.In addition,the structure and delithiation of Li_(x)C_(6)O_(6) and the impacts of its decomposition product on the PEO-LiTFSI solid electrolyte were also evaluated on the basis of the comprehensive physical characterizations and the density functional theory(DFT)calculations.These findings open a new avenue for elevating the energy density and/or elongate the lifespan of the solid-state secondary batteries.展开更多
基金supported by the National Key Basic Research Program of China (No.2014CB932400)Joint Fund of the National Natural Science Foundation of China (No.U1401243)+2 种基金National Natural Science Foundation of China (No.51232005)Shenzhen Technical Plan Project (No.JCYJ20150529164918735,CYJ20170412170911187,KQJSCX20160226191136)Guangdong Technical Plan Project (No.2015TX01N011)。
文摘In this work, the electrochemical performance of LiNi0.8Co0.1Mn0.1O2(NCM811) has been investigated after cycling with various upper cutoff voltages. Noteworthily, electrochemical impedance of NCM811 declined with the increasing cycle number to high voltages. It was found that the decline of charge transfer impedance could be related to the structural and compositional change of cathode electrolyte interphase(CEI) of NCM811 when charging to high voltages, based on the characterization of electrochemical impedance spectroscopy(EIS), X-ray photoelectron spectroscopy(XPS) and transmission electron microscopy(TEM). The corresponding mechanism has also been proposed in this study. Specifically, due to the increasing roughness of cathode surface, the bottom of CEI film and cubic phase on cathode surface form a transition region mainly at high voltages, leading to the nonobvious boundary. This newly formed transition region at high voltages could promote the Li ion diffusion from electrolyte to cathode, then reducing charge transfer impedance. Additionally, the decrease of Li F on the surface of the cathode could also make a contribution to lower the interface impedance. This study delivers a different evolution of CEI on NCM811, and the impact of CEI evolution on electrochemical performance when charging to a high voltage.
基金supported by the National Natural Science Foundation of China(51804290,22075025,21975026)the Beijing Natural Science Foundation(L182023)+1 种基金the Science and Technology Program of Guangdong Province(Grant No.2020B0909030004)the Beijing Institute of Technology Research Fund Program for Young Scholars(2019CX04092)。
文摘With the advancement of secondary batteries,interfacial properties of electrode materials have been recognized as essential factors to their electrochemical performance.However,the majority of investigations are devoted into advanced electrode materials synthesis,while there is insufficient attention paid to regulate their interfaces.In this regard,the solid electrolyte interphase(SEI)at anode part has been studied for 40 years,already achieving remarkable outcomes on improving the stability of anode candidates.Unfortunately,the study on the cathode electrolyte interfaces(CEI)remains in infancy,which constitutes a potential restriction to the capacity contribution,stability and safety of cathodes.In fact,the native CEI generally possesses unfavorable characteristics against structural and compositional stability that requires demanding optimization strategies.Meanwhile,an in-depth understanding of the CEI is of great significance to guide the optimization principles in terms of composition,structure,growth mechanism,and electrochemical properties.In this literature,recent progress and advances of the CEI characterization methods and optimization protocols are summarized,and meanwhile the mutually-reinforced mechanisms between detection and modification are explained.The criteria and the potential development of the CEI characterization are proposed with insights of novel optimization directions.
基金supported by the National Science Foundation of China(No.21776105)the Natural Science Foundation of Guangdong Province(No.2019A1515011720)Science and Technology Program of Guangzhou(No.201904010340).
文摘Lithium-sulfur batteries(LSBs)are regarded as the most promising next-generation energy system due to their high theoretical energy density.However,LSBs suffer the“shuttle effect”if undergoing the solid-liquid-solid sulfur conversion process during cycling.Herein,we design a solvent-in-salt(SIS)electrolyte with co-solvent vinylene carbonate(VC)to synthesize an in situ dense cathode electrolyte interface(CEI)and successfully change sulfur conversion into a solid-solid way to avoid shuttle effect by separating the contact of sulfur and ether solvent.Dense CEI is formed at the beginning of first discharge by the combined action of SIS electrolyte and filmogen VC.Experiments and simulations show that SIS electrolyte controls the initial formed lithium polysulfides(LiPSs)to stay very closely on the cathode surface,and then converts them into a dense CEI film.As a result,Coulombic efficiency(above 99%)and cycling performance of LSBs are improved.Furthermore,the in situ dense CEI can nearly stop the self-discharge of LSBs,and enable the LSBs to work under a pretty lean electrolyte condition.
基金supported partially by the Natural Science Foundation of Beijing Municipality (L172036)the Joint Funds of the Equipment Pre-Research and Ministry of Education (6141A020225)+2 种基金the National Natural Science Foundation of China (Grants Nos. 52072323 and 51872098)the Science and Technology Beijing 100 Leading Talent Training Projectthe NCEPU ‘‘Double First-Class” Program. We thank Dr. Rui Liu for suggestions on the crystal structure analysis。
文摘Li-rich layered oxide cathodes have received considerable attention because of the high operating potential and specific capacity. However, the structural instability and parasitic reactions at high potential cause severe degradation of the electrochemical performance. In our studies, the cycling stability of Li_(1.14)Ni_(0.133)Co_(0.133)Mn_(0.544)O_(2) cathode is improved with LiPO_(2)F_(2) electrolyte additive. After 500 cycles, the capacity retention is increased from 53.6% to 85% at 3 C by LiPO_(2)F_(2) modification. This performance is mainly attributed to the enhanced interfacial stability of the Li-rich cathode. Based on systematic characterization, LiPO_(2)F_(2) additive was found to promote a stable interface film on the cathode surface during the cycling and mitigates the interfacial side reactions. This study provides new insights for improving high-potential Li-rich layered oxide batteries.
基金support from the Na-tional Key R&D Program of China(Grant No.2023YFE0202000)National Natural Science Foundation of China(No.52102213)Science Technology Program of Jilin Province(No.20230101128JC).
文摘With the continuous advancement of industrialization,sodium-ion batteries(SIBs)need to operate in various challenging circumstances,particularly in extremely cold conditions.However,at ultra-low tem-peratures,the reduced ionic conductivity and sluggish Na+migration of commonly carbonate-based elec-trolytes will inevitably lead to a sharp decrease in the capacity of SIBs.Herein,we design a carboxylate ester-based electrolyte with excellent ultra-low temperature performance by straightforward cosolvent strategy.Due to the low viscosity,melting point,and sufficient ionic conductivity of the designed elec-trolyte,the resulting Na||Na_(3)V_(2)(PO_(4))_(2)O_(2)F can achieve the capacity retention of 96%(100 cycles at 0.1 C)at-40℃ and can also operate stably even at-50℃.Besides,galvanostatic intermittent titration tech-nique(GITT),ex-situ X-ray photoelectron spectroscopy(XPS),and high-resolution transmission electron microscopy(TEM)tests are employed to analyze and confirm that the carboxylate ester-based electrolyte promotes robust and uniform cathode/electrolyte interface layer formation and accelerates ion diffusion kinetics,which collectively facilitates the better low-temperature performance.In addition,the assembled hard carbon||NVPOF full cells further prove the practicability of the carboxylate ester-based electrolyte at low-temperature,which delivers high discharge capacity of 108.4 and 73.0 mAh g^(-1) at-25 and-40℃.This work affords a new avenue for designing advanced low-temperature electrolytes for SIBs.
基金Project(2023QNRC001)supported by the Young Elite Scientists Sponsorship Program by CAST,ChinaProject(51932011)supported by the National Natural Science Foundation of China+1 种基金Project(2023JJ10060)supported by the Natural Science Foundation of Hunan Province,ChinaProject(23A0003)supported by the Scientific Research Fund of Hunan Provincial Education Department,China。
文摘High-voltage sodium-ion batteries(SIBs)are emerging as promising candidates for large-scale energy storage systems due to their abundant sodium source and high energy density.However,the instability of the electrode electrolyte interphase remains a critical barrier to the potential use of high-voltage SIBs.Herein,sodium difluorophosphate(NaDFP)and fluoroethylene carbonate(FEC)serve as functional electrolyte additives to stabilize the interface of the high-voltage cathode.The oxidative competition between FEC and NaDFP facilitates the robust formation of the cathode-electrolyte interface(CEI)layer,enriched with inorganic components such as NaF/NaPO_(x)F_(y).The highly conductive NaF/NaPO_(x)F_(y)and inorganics provide fast ion transport pathways and mechanical strength,thereby mitigating the decomposition of carbonates and NaPF_(6).The half-cell equipped with BE 2 F+0.5 DFP demonstrates 93.9%capacity retention at 4.3 V across 600 cycles,showcasing excellent cycling capability.Full HC||NVOPF cells exhibit sustained performance with 91.69%capacity retention and a capacity of 91.57 mA·h/g over 1000 cycles at a 5 C rate.This study is poised to garner increased scholarly interest in the domain of rational electrolyte formulation for practical applications.
文摘All-solid-state batteries potentially exhibit high specific energy and high safety,which is one of the development directions for nextgeneration lithium-ion batteries.The compatibility of all-solid composite electrodes with high-nickel layered cathodes and inorganic solid electrolytes is one of the important problems to be solved.In addition,the interface and mechanical problems of high-nickel layered cathodes and inorganic solid electrolyte composite electrodes have not been thoroughly addressed.In this paper,the possible interface and mechanical problems in the preparation of high-nickel layered cathodes and inorganic solid electrolytes and their interface reaction during charge–discharge and cycling are reviewed.The mechanical contact problems from phenomena to internal causes are also analyzed.Uniform contact between the high-nickel cathode and solid electrolyte in space and the ionic conductivity of the solid electrolyte are the prerequisites for the good performance of a high-nickel layered cathode.The interface reaction and contact loss between the high-nickel layered cathode and solid electrolyte in the composite electrode directly affect the passage of ions and electrons into the active material.The buffer layer constructed on the high-nickel cathode surface can prevent direct contact between the active material and electrolyte and slow down their interface reaction.An appropriate protective layer can also slow down the interface contact loss by reducing the volume change of the high-nickel layered cathode during charge and discharge.Finally,the following recommendations are put forward to realize the development vision of high-nickel layered cathodes:(1)develop electrochemical systems for high-nickel layered cathodes and inorganic solid electrolytes;(2)elucidate the basic science of interface and electrode processes between high-nickel layered cathodes and inorganic solid electrolytes,clarify the mechanisms of the interfacial chemical and electrochemical reactions between the two materials,and address the intrinsic safety issues;(3)strengthen the development of research and engineering technologies and their preparation methods for composite electrodes with high-nickel layered cathodes and solid electrolytes and promote the industrialization of all-solid-state batteries.
基金supported by the National Natural Science Foundation of China(51962019)the Natural Science Foundation of Gansu Province(20JR5RA469)+1 种基金the Education Department of Gansu Province:"Star of Innovation"Project for Outstanding Graduate Students(2021CXZX-455)the Lanzhou University of Technology Hongliu First-class Discipline Construction Program。
文摘Tris(trimethylsilyl)borate(TMSB) has been intensively studied to improve the performances of lithiumion batteries. However, it is still an interesting issue needed to be resolved for the research on the Li^(+) solvation structure affected by TMSB additive. Herein, the electrochemical tests, quantum chemistry calculations, potential-resolved in-situ electrochemical impedance spectroscopy measurements and surface analyses were used to explore the effects of Li^(+) solvation structure with TMSB additive on the formation of the cathode electrolyte interface(CEI) film in LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)/Li half cells. The results reveal that the TMSB additive is easy to complex with Li^(+) ion, thus weaken the intermolecular force between Li^(+) ions and ethylene carbonate solvent, which is benefit for the cycle performance. Besides, the changed Li^(+) solvation structure results in a thin and dense CEI film containing compounds with Si–O and B–O bonds which is favorable to the transfer of Li^(+) ions. As a result, the performances of the LNCM811/Li half cells are effectively improved. This research provides a new idea to construct a high-performance CEI film by adjusting the Li^(+) solvation structures.
基金supported by the National Natural Science Foundation of China(Nos.21965034,52061135110,U1903217,52162036,22065033,21905242,and 22075305)the Key Project of Nature Science Foundation of Xinjiang Province(No.2021D01D08)+4 种基金the Xinjiang Autonomous Region Major Projects(Nos.2022A01005-4 and 2021A01001-1)the Natural Science Foundation of Zhejiang Province(No.LD22E020003)the Ningbo Science&Technology Innovation 2025 Major Project(No.2020Z024)the Foundation of State Key Laboratory of Chemistry and Utilization of Carbon-based Energy Resource(No.KFKT2022004)Key Laboratory of Bio-based Polymeric Materials of Zhejiang Province.
文摘LiNi0.8Co0.1Mn0.1O_(2)(NCM811),a Ni-rich layered oxide,is a promising cathode material for high-energy density lithium-ion batteries(LIBs).However,its structural instability,caused by adverse phase transitions and continuous oxygen release,as well as deteriorated interfacial stability due to excessive electrolyte oxidative decomposition,limits its widespread application.To address these issues,a new concept is proposed that surface targeted precise functionalization(STPF)of the NCM811 cathode using a synergistic slurry additive(SSA)approach.This approach involves coating the NCM811 particle surface with 3-aminopropyl dimethoxy methyl silane(3-ADMS),followed by the precise deposition of ascorbic acid via an acid-base interaction.The slurry additives induce the formation of an ultra-thin spinel surface layer and a stable cathode–electrolyte interface(CEI),which enhances the electrochemical kinetics and inhibits crack propagation.The STPF strategy implemented by the SSA approach significantly improves the cyclic stability and rate performance of the NCM811 cathode in both half-cell and full-cell configurations.This work establishes a promising strategy to enhance the structural stability and electrochemical performance of nickel-rich cathodes and provides a feasible route to promote practical applications of high-energy density lithium-ion battery technology.
基金financially supported by the National Natural Science Foundation of China(NSFC No.22075316,U23A20577,22005334,and 52172257)the Natural Science Foundation of Beijing(Grant No.Z200013).
文摘The continuous lithium consumption during cycling severely reduces the energy density of the lithium battery,and thus,lithium compensation is essential.Herein,Li_(x)C_(6)O_(6)(x=2,4)was proposed as an air-stable high-efficiency sacrificial additive in the cathode to compensate for the lost lithium ions in solid-state lithium batteries.Below a delithiation(oxidation)potential as low as 3.8 V,Li_(2)C_(6)O_(6) can release most of its Li^(+)ions(294.8 mAh g^(−1) in theory).Similarly,Li_(4)C_(6)O_(6) is also characteristic of low oxidation potential and high delithiation capacity(547.8 mAh g^(−1) in theory).The feasibility of using Li_(x)C_(6)O_(6) as the self-sacrificial additive in the cathode was verified with the marked increase of the initial charge capacity of the Li||LiFePO_(4)(half)cells and the initial discharge capacity of Cu||LiFePO_(4)(full)cells,and the improved electrolyte/cathode interface stability and interface contact,in the solid-state poly(ethylene oxide)-lithium bis(trifluoromethane)sulfonimide(PEO-LiTFSI)electrolyte.In addition,the structure and delithiation of Li_(x)C_(6)O_(6) and the impacts of its decomposition product on the PEO-LiTFSI solid electrolyte were also evaluated on the basis of the comprehensive physical characterizations and the density functional theory(DFT)calculations.These findings open a new avenue for elevating the energy density and/or elongate the lifespan of the solid-state secondary batteries.
