Silicon(Si),a promising high-capacity anode material for lithium-ion batteries,suffers from severe volume changes upon cycling,leading to rapid capacity fading.This study mitigates the capacity fading issue by introdu...Silicon(Si),a promising high-capacity anode material for lithium-ion batteries,suffers from severe volume changes upon cycling,leading to rapid capacity fading.This study mitigates the capacity fading issue by introducing a surface SiNx layer on micron Si,which is in-situ converted into a LixSiNy-based artificial solid electrolyte interphase(SEI).This artificial SEI not only effectively restricts SEI growth to the outmost surface,but also induces a self-optimized structural evolution of the inner Si from micron particles to nanoporous network within 20 cycles.This self-optimized nanoprous Si network exhibits low volume expansion and enhanced reaction kinetics.Consequently,the Si@SiNx/TiN demonstrates a high capacity,stable cycling,and good fast-charging capability.展开更多
Carbon coati ng has bee n a routi ne strategy for improvi ng the performa nee of Si-based anode materials for lithium-ion batteries. The ability to tailor the thick ness, homoge neity and graph itizati on degree of ca...Carbon coati ng has bee n a routi ne strategy for improvi ng the performa nee of Si-based anode materials for lithium-ion batteries. The ability to tailor the thick ness, homoge neity and graph itizati on degree of carb on-coati ng layers is esse ntial for addressi ng issues that hamper the real applicatio ns of Si anodes. Herein, we report the con structio n of two-dime nsional (2D) assemblies of intercon nected Si @ graphitic carb on yolk-shell nano particles (2D-Si@gC) from commercial Si powders by exploiting oleic acid (OA). The OA molecules act as both the surface-coati ng liga nds for facilitating 2D nano particle assembly and the precursor for forming uniform and conformal graphitic shells as thin as 4 nm. The as-prepared 2D-Si@gC with rationally designed void space exhibits excellent rate capability and cycling stability when used as anode materials for lithium-ion batteries, delivering a capacity of 1,150 mAh·g^-1 at an ultrahigh current density of 10 A·g^-1 and maintaining a stabilized capacity of 1,275 mAh·g^-1 after 200 cycles at 4 A·g^-1 The formatio n of yolk-shell nano particles 8nfines the depositi on of solid electrolyte in terphase (SEI) onto the outer carb on shell, while simulta neously providing sufficie nt space for volumetric expa nsion of Si nano particles. These attributes effectively mitigate the thickness variations of the entire electrode during repeated lithiation and delithiation, which combined with the unique 2D architecture and interc onn ected graphitic carbon shells of 2D-Si@gC contributes to its superior rate capability and cycling performa nee.展开更多
基金supported by the National Key Research and Development Program of China(2022YFB3803501)the Key Research and Development Program of Hubei Province(2021BAA176)+1 种基金the Hainan Provincial Natural Science Foundation of China(522CXTD516)the Science and Technology special fund of Hainan Province(ZDYF2025GXJS008)。
文摘Silicon(Si),a promising high-capacity anode material for lithium-ion batteries,suffers from severe volume changes upon cycling,leading to rapid capacity fading.This study mitigates the capacity fading issue by introducing a surface SiNx layer on micron Si,which is in-situ converted into a LixSiNy-based artificial solid electrolyte interphase(SEI).This artificial SEI not only effectively restricts SEI growth to the outmost surface,but also induces a self-optimized structural evolution of the inner Si from micron particles to nanoporous network within 20 cycles.This self-optimized nanoprous Si network exhibits low volume expansion and enhanced reaction kinetics.Consequently,the Si@SiNx/TiN demonstrates a high capacity,stable cycling,and good fast-charging capability.
基金A. D. acknowledges the financial support from the National Natural Science Foundation of China (Nos. 21872038 and 21373052)MOST (No. 2017YFA0207303)+1 种基金Key Basic Research Program of Science and Technology Commission of Shanghai Municipality (No. 17JC1400100)D. Y. thanks to the National Natural Science Foundation of China (Nos. 51573030, 51573028 and 51773042).
文摘Carbon coati ng has bee n a routi ne strategy for improvi ng the performa nee of Si-based anode materials for lithium-ion batteries. The ability to tailor the thick ness, homoge neity and graph itizati on degree of carb on-coati ng layers is esse ntial for addressi ng issues that hamper the real applicatio ns of Si anodes. Herein, we report the con structio n of two-dime nsional (2D) assemblies of intercon nected Si @ graphitic carb on yolk-shell nano particles (2D-Si@gC) from commercial Si powders by exploiting oleic acid (OA). The OA molecules act as both the surface-coati ng liga nds for facilitating 2D nano particle assembly and the precursor for forming uniform and conformal graphitic shells as thin as 4 nm. The as-prepared 2D-Si@gC with rationally designed void space exhibits excellent rate capability and cycling stability when used as anode materials for lithium-ion batteries, delivering a capacity of 1,150 mAh·g^-1 at an ultrahigh current density of 10 A·g^-1 and maintaining a stabilized capacity of 1,275 mAh·g^-1 after 200 cycles at 4 A·g^-1 The formatio n of yolk-shell nano particles 8nfines the depositi on of solid electrolyte in terphase (SEI) onto the outer carb on shell, while simulta neously providing sufficie nt space for volumetric expa nsion of Si nano particles. These attributes effectively mitigate the thickness variations of the entire electrode during repeated lithiation and delithiation, which combined with the unique 2D architecture and interc onn ected graphitic carbon shells of 2D-Si@gC contributes to its superior rate capability and cycling performa nee.
