Preparation and electrochemical lithium storage performance of porous silicon microsphere composite with metal modification and carbon coating
This work adopts a multi-step etching-heat treatment strategy to prepare porous silicon microsphere com-posite with Sb-Sn surface modification and carbon coating(pSi/Sb-Sn@C),using industrial grade SiAl alloy micro-spheres as a precursor.pSi/Sb-Sn@C had a 3D structure with bimetallic(Sb-Sn)modified porous silicon micro-spheres(pSi/Sb-Sn)as the core and carbon coating as the shell.Carbon shells can improve the electronic conductivi-ty and mechanical stability of porous silicon microspheres,which is beneficial for obtaining a stable solid electrolyte interface(SEI)film.The 3D porous core promotes the diffusion of lithium ions,increases the intercalation/delithia-tion active sites,and buffers the volume expansion during the intercalation process.The introduction of active met-als(Sb-Sn)can improve the conductivity of the composite and contribute to a certain amount of lithium storage ca-pacity.Due to its unique composition and microstructure,pSi/Sb-Sn@C showed a reversible capacity of 1 247.4 mAh·g-1 after 300 charge/discharge cycles at a current density of 1.0 A·g-1,demonstrating excellent rate lithium storage performance and enhanced electrochemical cycling stability.
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