The fluid model,also called the macroscopic model,is commonly used to simulate low temperature and low pressure radiofrequency plasma discharges.By varying the parameters of the model,numerical simulation allows us to...The fluid model,also called the macroscopic model,is commonly used to simulate low temperature and low pressure radiofrequency plasma discharges.By varying the parameters of the model,numerical simulation allows us to study several cases,providing us the physico-chemical information that is often difficult to obtain experimentally.In this work,using the fluid model,we employ numerical simulation to show the effect of pressure and space between the reactor electrodes on the fundamental properties of silicon plasma diluted with ammonia and hydrogen.The results show the evolution of the fundamental characteristics of the plasma discharge as a function of the variation of the pressure and the distance between the electrodes.By examining the pressure-distance product in a range between 0.3 Torr 2.7 cm and 0.7 Torr 4 cm,we have determined the optimal pressure-distance product that allows better deposition of hydrogenated silicon nitride(SiN_(x)H_(y))films which is 0.7 Torr 2.7 cm.展开更多
Silicon (Si) is a promising anode material for next-generation high-energy lithium-ion batteries (LIBs) due to its high capacity.However,the large volumetric expansion,poor ion conductivity and unstable solid electrol...Silicon (Si) is a promising anode material for next-generation high-energy lithium-ion batteries (LIBs) due to its high capacity.However,the large volumetric expansion,poor ion conductivity and unstable solid electrolyte interface (SEI) lead to rapid capacity fading and low rate performance.Herein,we report Si nitride (SiN) comprising stoichiometric Si_(3)N_(4) and Li-active anazotic SiN_(x) coated porous Si (p-Si@SiN)for high-performance anodes in LIBs.The ant-nest-like porous Si consisting of 3D interconnected Si nanoligaments and bicontinuous nanopores prevents pulverization and accommodates volume expansion during cycling.The Si_(3)N_(4) offers mechanically protective coating to endow highly structural integrity and inhibit superfluous formation of SEI.The fast ion conducting Li_(3)N generated in situ from lithiation of active SiN_(x) facilitates Li ion transport.Consequently,the p-Si@SiN anode has appealing electrochemical properties such as a high capacity of 2180 mAh g^(-1)at 0.5 A g^(-1) with 84%capacity retention after 200cycles and excellent rate capacity with discharge capacity of 721 mAh g^(-1) after 500 cycles at 5.0 A g^(-1).This work provides insights into the rational design of active/inactive nanocoating on Si-based anode materials for fast-charging and highly stable LIBs.展开更多
基金the National Natural Science Foundation of China(62304252)the Youth Innovation Promotion Association of Chinese Academy Sciences(CAS)and IMECAS-HKUST-Joint Laboratory of Microelectronics。
文摘The fluid model,also called the macroscopic model,is commonly used to simulate low temperature and low pressure radiofrequency plasma discharges.By varying the parameters of the model,numerical simulation allows us to study several cases,providing us the physico-chemical information that is often difficult to obtain experimentally.In this work,using the fluid model,we employ numerical simulation to show the effect of pressure and space between the reactor electrodes on the fundamental properties of silicon plasma diluted with ammonia and hydrogen.The results show the evolution of the fundamental characteristics of the plasma discharge as a function of the variation of the pressure and the distance between the electrodes.By examining the pressure-distance product in a range between 0.3 Torr 2.7 cm and 0.7 Torr 4 cm,we have determined the optimal pressure-distance product that allows better deposition of hydrogenated silicon nitride(SiN_(x)H_(y))films which is 0.7 Torr 2.7 cm.
基金Supported by the National Natural Science Foundation of China (61822407,62074161,62004213)the National Key Research and Development Program of China under (2018YFE0125700)。
基金financially supported by the National Natural Science Foundation of China (U2004210, 51974208, U2003130, 21875080, 52002297)the Outstanding Youth Foundation of Natural Science Foundation of Hubei Province (2020CFA099)+2 种基金the Special Project of Central Government for Local Science and Technology Development of Hubei Province (2019ZYYD024)the Innovation group of Natural Science Foundation of Hubei Province (2019CFA020)the City University of Hong Kong Strategic Research Grants (7005505)。
文摘Silicon (Si) is a promising anode material for next-generation high-energy lithium-ion batteries (LIBs) due to its high capacity.However,the large volumetric expansion,poor ion conductivity and unstable solid electrolyte interface (SEI) lead to rapid capacity fading and low rate performance.Herein,we report Si nitride (SiN) comprising stoichiometric Si_(3)N_(4) and Li-active anazotic SiN_(x) coated porous Si (p-Si@SiN)for high-performance anodes in LIBs.The ant-nest-like porous Si consisting of 3D interconnected Si nanoligaments and bicontinuous nanopores prevents pulverization and accommodates volume expansion during cycling.The Si_(3)N_(4) offers mechanically protective coating to endow highly structural integrity and inhibit superfluous formation of SEI.The fast ion conducting Li_(3)N generated in situ from lithiation of active SiN_(x) facilitates Li ion transport.Consequently,the p-Si@SiN anode has appealing electrochemical properties such as a high capacity of 2180 mAh g^(-1)at 0.5 A g^(-1) with 84%capacity retention after 200cycles and excellent rate capacity with discharge capacity of 721 mAh g^(-1) after 500 cycles at 5.0 A g^(-1).This work provides insights into the rational design of active/inactive nanocoating on Si-based anode materials for fast-charging and highly stable LIBs.
