As a negative electrode material for lithium-ion batteries,silicon monoxide(SiO)suffers from dramatic volume changes during cycling,causing excessive stress within the electrode and resulting in electrode deformation ...As a negative electrode material for lithium-ion batteries,silicon monoxide(SiO)suffers from dramatic volume changes during cycling,causing excessive stress within the electrode and resulting in electrode deformation and fragmentation.This ultimately leads to a decrease in cell capacity.The trends of volume expansion and capacity change of the SiO/graphite(SiO/C)composite electrode during cycling were investigated via in situ expansion monitoring.First,a series of expansion test schemes were designed,and the linear relationship between negative electrode expansion and cell capacity degradation was quantitatively analyzed.Then,the effects of different initial pressures on the long-term cycling performance of the cell were evaluated.Finally,the mechanism of their effects was analyzed by scanning electron microscope.The results show that after 50 cycles,the cell capacity decreases from 2.556 mAh to 1.689 mAh,with a capacity retention ratio(CRR)of only 66.08%.A linear relationship between the capacity retention ratio and thickness expansion was found.Electrochemical measurements and scanning electron microscope images demonstrate that intense stress inhibits the lithiation of the negative electrode and that the electrode is more susceptible to irreversible damage during cycling.Overall,these results reveal the relationship between the cycling performance of SiO and the internal pressure of the electrode from a macroscopic point of view,which provides some reference for the application of SiO/C composite electrodes in lithium-ion batteries.展开更多
Silicon monoxide(SiO)is highly attractive as an anode material for high-energy lithium-ion batteries(LIBs)due to its significantly higher specific capacity.However,its practical application is hindered by substantial ...Silicon monoxide(SiO)is highly attractive as an anode material for high-energy lithium-ion batteries(LIBs)due to its significantly higher specific capacity.However,its practical application is hindered by substantial volume expansion during cycling,which leads to material pulverization and an unstable solid electrolyte interphase(SEI)layer.Inspired by the natural root fixation in soil,we designed a root-like topological structure binder,cassava starch-citric acid(CS-CA),based on the synergistic action of covalent and hydrogen bonds.The abundant-OH and-COOH groups in CS-CA molecules effectively form hydrogen bonds with the-OH groups on the SiO surface,significantly enhancing the interfacial interaction between CS-CA and SiO.The root-like topological structure of CS-CA with a high tolerance alleviates the mechanical stress generated by the volume changes of SiO.More encouragingly,the hydrogen bond action among CS-CA molecules produces a self-healing effect,which is advantageous for repairing damaged electrodes and preserving their structural integrity.As such,the CS-CA/SiO electrode exhibits exceptional cycling performance(963.1 mA h g^(-1)after 400 cycles at 2 A g^(-1))and rate capability(558.9 mA h g^(-1)at 5 A g^(-1)).This innovative,topologically interconnected,root-inspired binder will greatly advance the practical application of long-lasting micron-sized SiO anodes.展开更多
基金supported by the Fundamental Research Funds for the Central Universities(WK2090000055)Anhui Provincial Natural Science Foundation of China(2308085QG231).
文摘As a negative electrode material for lithium-ion batteries,silicon monoxide(SiO)suffers from dramatic volume changes during cycling,causing excessive stress within the electrode and resulting in electrode deformation and fragmentation.This ultimately leads to a decrease in cell capacity.The trends of volume expansion and capacity change of the SiO/graphite(SiO/C)composite electrode during cycling were investigated via in situ expansion monitoring.First,a series of expansion test schemes were designed,and the linear relationship between negative electrode expansion and cell capacity degradation was quantitatively analyzed.Then,the effects of different initial pressures on the long-term cycling performance of the cell were evaluated.Finally,the mechanism of their effects was analyzed by scanning electron microscope.The results show that after 50 cycles,the cell capacity decreases from 2.556 mAh to 1.689 mAh,with a capacity retention ratio(CRR)of only 66.08%.A linear relationship between the capacity retention ratio and thickness expansion was found.Electrochemical measurements and scanning electron microscope images demonstrate that intense stress inhibits the lithiation of the negative electrode and that the electrode is more susceptible to irreversible damage during cycling.Overall,these results reveal the relationship between the cycling performance of SiO and the internal pressure of the electrode from a macroscopic point of view,which provides some reference for the application of SiO/C composite electrodes in lithium-ion batteries.
基金supported by the National Natural Science Foundation of China(Grant Nos.22378342,92372101,52162036,and 21875155)the Fundamental Research Funds for the Central Universities(20720220010)+3 种基金the National Key Research and Development Program of China(2021YFA1201502)the Natural Science Foundation of Sichuan Province(Grant No.2024NSFSC1160)the Postdoctoral Fellowship Program of CPSF(Grant No.GZB20230608)support of Nanqiang Young Top-notch Talent Fellowship in Xiamen University。
文摘Silicon monoxide(SiO)is highly attractive as an anode material for high-energy lithium-ion batteries(LIBs)due to its significantly higher specific capacity.However,its practical application is hindered by substantial volume expansion during cycling,which leads to material pulverization and an unstable solid electrolyte interphase(SEI)layer.Inspired by the natural root fixation in soil,we designed a root-like topological structure binder,cassava starch-citric acid(CS-CA),based on the synergistic action of covalent and hydrogen bonds.The abundant-OH and-COOH groups in CS-CA molecules effectively form hydrogen bonds with the-OH groups on the SiO surface,significantly enhancing the interfacial interaction between CS-CA and SiO.The root-like topological structure of CS-CA with a high tolerance alleviates the mechanical stress generated by the volume changes of SiO.More encouragingly,the hydrogen bond action among CS-CA molecules produces a self-healing effect,which is advantageous for repairing damaged electrodes and preserving their structural integrity.As such,the CS-CA/SiO electrode exhibits exceptional cycling performance(963.1 mA h g^(-1)after 400 cycles at 2 A g^(-1))and rate capability(558.9 mA h g^(-1)at 5 A g^(-1)).This innovative,topologically interconnected,root-inspired binder will greatly advance the practical application of long-lasting micron-sized SiO anodes.
