Prevention of Solid Electrolyte lnterphase Damaging on Silicon by Using Polymer Derived SiCN Ceramics

摘要

A new composite anode material for lithium ion batteries, based on nano-silicon particles dispersed in a polymer-derived ceramic (PDC) matrix, was produced, characterized and electrochemically analyzed via cyclic voltammetry (CV). For this purpose a commercial preceramic polymer , namely the polysilazane HTT 1800, was mixed with silicon nano powder and pyrolyzed at 900, 1100, 1300 and 1500 ℃. It was found that in comparison with pure silicon, the composite presented an enhanced electrochemical stability during lithium insertion/extraction. Moreover, dispersing the silicon into the ceramic matrix avoids a continuous energy loss related to the formation of a solid electrolyte interphase (SE1). By means of cyclic voltammetry measurements we found that for the composites synthesized at temperatures exceeding 1000 ℃, no more losses were observable during subsequent insertion/extraction once the stable SE1 was formed.