Few-Layer Siloxene as an Electrode for Superior High-Rate Zinc Ion Hybrid Capacitors

Zinc ion hybrid capacitors have emerged as promising energy storage devices due to the attributes of high energy density and superb power output. The current electrode materials applied to zinc ion hybrid capacitors are mainly various carbon and MXenes. Therefore, there are great demands for developing electrode materials for zinc ion hybrid capacitors. Considering the boom of silicon semiconductor technology, the integration of silicon-based materials into zinc ion hybrid capacitors is desirable and appreciable. Few-layer siloxene is reported here in the development of the cathode of a zinc ion hybrid capacitor, which has a maximum specific capacitance of 6.86 mF cm-2, a maximum power density of 4.50 mW cm-2, and a maximum energy density of 10.66 mJ cm-2, surpassing those of silicon-based supercapacitors. In addition, this hybrid capacitor retains a capacitance retention of 94.3% over 16000 cycles. These results highlight the promising possibility of siloxene as an electrode material for future energy storage applications.