Self-standing mesoporous Si films as anodes for lithium-ion microbatteries

Silicon is the most promising anode material for next-generation lithium-ion batteries (LIBs) due to its high theoretical specific capacity and safe electrochemical potential. Among the different Si materials, mesoporous Si has attracted attention as the pores can accommodate the volume expansion during cycling, thus leading to stable battery cycling. However, carbon is often added to the electrode to improve the performance of the porous Si electrodes. To investigate the sole effects of the pore characteristics on the battery performance without any contribution from carbon, we produce self-standing mesoporous Si films with different porous structures through electrochemical etching and prepare electrodes without carbon additives or binders. Detailed pore analysis and electrochemical characterization of the Si films are performed to study their correlation. Correlation analysis shows that both reversible specific capacity and initial Coulombic efficiency (ICE) are mainly affected by the porosity and surface area, while the cycling performance is dictated by the film thickness over the pore char-acteristics. The best Si film anode delivers an ICE of 81.2% and stable cycling for over 450 cycles with a limited specific capacity of 1200 mAh g(-1) in half cells. This study indicates the direction of the porous silicon material for high-performance LIBs.

Automated summary

Silicon is a highly promising anode material for next-generation lithium-ion batteries due to its high capacity and safe potential. Mesoporous silicon has been widely studied for its ability to accommodate volume expansion during cycling and provide stable battery performance. This research investigates the impact of pore characteristics on battery performance by producing self-standing mesoporous silicon films without carbon additives. The study finds that porosity and surface area greatly affect specific capacity and initial Coulombic efficiency, while cycling performance is mainly determined by film thickness. The best mesoporous silicon film anode achieves stable cycling for over 450 cycles with an initial Coulombic efficiency of 81.2% and a limited specific capacity of 1200 mAh/g. This study provides valuable insights for the development of high-performance lithium-ion batteries.