Foamed Mesoporous C/Si Composite Nanofibers Anode for Lithium Ion Batteries

A new porous composite nanofiber manufacturing route, combining electrospinning and foaming processes, was developed. Aluminum acetylacetonate was dissolved in a polyacrylonitrile (PAN)/ silicon nanoparticles suspension solution as the foaming agent. PAN composite nanofibers were first produced by an electrospinning process with mesopores generated via a sublimation-based foaming process during later thermal stabilization treatment. After carbonization, the obtained mesoporous carbon/silicon composite nanofiber mats were explored as the anode material of lithium ion batteries. Within this composite anode, mesopores provide needed buffering space to accommodate the large volume expansion and consequent stress of silicon during lithiation. This effectively mitigated silicon pulverization issue and helped achieve higher reversible capacity and better capacity retention in later battery tests when compared with anodes made of nonporous composites nanofibers and carbon nanofibers alone.