Advancements in silicon-air batteries: High performance asymmetric-electrolyte and quasi-solid-state designs for portable applications

Abstract

Silicon-air batteries (SABs) hold significant potential as efficient energy conversion devices due to their high theoretical energy density, theoretical discharge voltage, and favorable energy-to-cost ratios. However, their applicability has been hindered by low output discharge potential, high discharge polarizations, and singular aqueous configuration. To address these, the catalyst with faster oxygen reduction reaction (ORR) kinetic rate, nitrogen-doped carbon materials functionalized with FeMo metal clusters (FeMo-NC), was designed in acid electrolyte and thus high output voltage and energy density SABs with asymmetric-electrolytes have been developed. This innovative design aligns the reaction rates of the cathode and anode in SABs, achieving stable discharge around 1.7 V for 188 h. Furthermore, an all-in-one quasi-solid-state SAB (QSSSAB) was first developed using a suitable acid–base gel electrolyte. This all-in-one QSSSAB showcases good safety, low cost, and portability, with open-circuit voltage of 1.6 V and energy density of 300.2 Wh kg⁻¹, surpassing the energy density of most previously reported aqueous SABs. In terms of application, these compact all-in-one QSSSABs can provide stable and reliable power support for portable small electronic devices (such as electronic players, diodes, and electronic watches).