In-depth study of annealed porous silicon: Understand the morphological properties effect on negative LiB electrode performance

Abstract

Silicon (Si) used as negative electrode in a Li-ion battery (LIB) is highly attractive for its high energy density, safe cycling, and nontoxicity. However its alloying mechanism with Li induces material pulverization, which leads to a rapid capacity fade. In this work, annealing post treatment was used in order to tune the morphological properties of porous silicon. Playing on annealing temperature, the morphological modification induces electrochemical behavior changes in LIB. The porosification is an interesting way to accommodate the volume expansion occurring during the alloying process. Increase of the annealing temperature leads to porous Si pores and walls reorganization, which has a positive impact on battery performance likely due to a higher wettability of the Si electrode with electrolyte. 700 °C appeared to be the optimized annealing temperature.