Graphite-silicon species(Gr-Si)hybrid anodes have merged as potential candidates for high-energy lithium-ion batteries(LIBs),yet long been plagued by rapid capacity fading due to their unstable mechano-electrochemistr...Graphite-silicon species(Gr-Si)hybrid anodes have merged as potential candidates for high-energy lithium-ion batteries(LIBs),yet long been plagued by rapid capacity fading due to their unstable mechano-electrochemistry.The dominant approach to enhance electrochemical stability of the Gr-Si hybrid anodes typically involves the optimization of the electrode material structures and the employment of low active Si species content in electrode(<10 wt%in most instances).However,the electrode structure design,a factor of equal importance in determining the electrochemical performance of Gr-Si hybrid anodes,has received scant attention.In this study,three Gr-Si hybrid anodes with the identical material composition but distinct electrode structures are designed to investigate the mechanoelectrochemistry of the electrodes.It is revealed that the substantial volume change of Si species particles in Gr-Si hybrid anodes led to the local lattice stress of Gr at their contact interface during the charge/discharge processes,thereby increasing thermodynamic and kinetic barrier of Li-ion migration.Furthermore,the huge disparity in volume change of Si species and Gr particles trigger the separate agglomeration of these two materials,resulting in a considerable electrode volume change and increased electrochemical resistance.An advanced Gr/Si hybrid anode with upper Gr and lower Si species layer structure design addresses the above challenges using photovoltaic waste silicon sources under high Si species content(17 wt%)and areal capacity(2.0 mA h cm^(-2))in Ah-level full pouch cells with a low negative/positive(N/P)ratio of 1.09.The cell shows stable cycling for 100 cycles at 0.3 C with an impressively low capacity decay rate of 0.0546%per cycle,outperforming most reported Gr-Si hybrid anodes.展开更多
Lithium-ion batteries(LIBs)with ether-based electrolytes usually provide low cell performance when matched with the graphite(Gr)anodes due to cointercalation of Li+-solvent.Herein,a novel deep eutectic ether electroly...Lithium-ion batteries(LIBs)with ether-based electrolytes usually provide low cell performance when matched with the graphite(Gr)anodes due to cointercalation of Li+-solvent.Herein,a novel deep eutectic ether electrolyte with polyethylene glycol dimethyl ether(PEGDME)featuring low flammability and high safety is developed,and fluoroethylene carbonate(FEC)is adopted to mitigate the cointercalation phenomenon.Unlike the common effect of FEC’s role in the first solvation shell,our results reveal that FEC molecules affect the Li+-PEGDME insertion behavior through FECPEGDME intramolecular interaction.As a result,a high discharge capacity of 450 mA h g^(−1)is achieved in Li||Gr/SiO_(x)cells at 50℃,and 370 mA h g^(−1)can be realized,even at−20℃(three times higher than commercial carbonate electrolyte).Moreover,Gr/SiO_(x)||LiNi_(0.6)Co_(0.2)Mn_(0.2O2)full cells maintain good capacity retention in both coin cell and pouch cell configurations over a wide temperature range.Our work deciphers the role of FEC as an additive and proposes new electrolyte optimization strategies to achieve high-performance all-climate LIBs.展开更多
基金the financial support by the National Natural Science Foundation of China(52072137)the National Natural Science Foundation of China(22205068)the"CUG Scholar"Scientific Research Funds at China University of Geosciences(Wuhan)(2022118)。
文摘Graphite-silicon species(Gr-Si)hybrid anodes have merged as potential candidates for high-energy lithium-ion batteries(LIBs),yet long been plagued by rapid capacity fading due to their unstable mechano-electrochemistry.The dominant approach to enhance electrochemical stability of the Gr-Si hybrid anodes typically involves the optimization of the electrode material structures and the employment of low active Si species content in electrode(<10 wt%in most instances).However,the electrode structure design,a factor of equal importance in determining the electrochemical performance of Gr-Si hybrid anodes,has received scant attention.In this study,three Gr-Si hybrid anodes with the identical material composition but distinct electrode structures are designed to investigate the mechanoelectrochemistry of the electrodes.It is revealed that the substantial volume change of Si species particles in Gr-Si hybrid anodes led to the local lattice stress of Gr at their contact interface during the charge/discharge processes,thereby increasing thermodynamic and kinetic barrier of Li-ion migration.Furthermore,the huge disparity in volume change of Si species and Gr particles trigger the separate agglomeration of these two materials,resulting in a considerable electrode volume change and increased electrochemical resistance.An advanced Gr/Si hybrid anode with upper Gr and lower Si species layer structure design addresses the above challenges using photovoltaic waste silicon sources under high Si species content(17 wt%)and areal capacity(2.0 mA h cm^(-2))in Ah-level full pouch cells with a low negative/positive(N/P)ratio of 1.09.The cell shows stable cycling for 100 cycles at 0.3 C with an impressively low capacity decay rate of 0.0546%per cycle,outperforming most reported Gr-Si hybrid anodes.
基金supported by the Jilin Province Science and Technology Department Major Science and Technology Project(grant nos.20220301004GX and 20220301005GX)Key Subject Construction of Physical Chemistry of Northeast Normal Universityand the National Natural Science Foundation of China(grant nos.22102020 and 22279014).
文摘Lithium-ion batteries(LIBs)with ether-based electrolytes usually provide low cell performance when matched with the graphite(Gr)anodes due to cointercalation of Li+-solvent.Herein,a novel deep eutectic ether electrolyte with polyethylene glycol dimethyl ether(PEGDME)featuring low flammability and high safety is developed,and fluoroethylene carbonate(FEC)is adopted to mitigate the cointercalation phenomenon.Unlike the common effect of FEC’s role in the first solvation shell,our results reveal that FEC molecules affect the Li+-PEGDME insertion behavior through FECPEGDME intramolecular interaction.As a result,a high discharge capacity of 450 mA h g^(−1)is achieved in Li||Gr/SiO_(x)cells at 50℃,and 370 mA h g^(−1)can be realized,even at−20℃(three times higher than commercial carbonate electrolyte).Moreover,Gr/SiO_(x)||LiNi_(0.6)Co_(0.2)Mn_(0.2O2)full cells maintain good capacity retention in both coin cell and pouch cell configurations over a wide temperature range.Our work deciphers the role of FEC as an additive and proposes new electrolyte optimization strategies to achieve high-performance all-climate LIBs.
