Diatomite templated layered NiO/NiS2 composite electrodes for high-performance supercapacitors toward wireless charging devices

A dual-surface growth strategy fully utilized the hollow architecture of diatomite. • A layered NiO/NiS 2 composite was constructed through in situ sulfurization. • FIB analysis directly verified active-material growth on inner and outer surfaces. • The synergistic interaction at the NiO/NiS 2 composite promoted charge-transfer kinetics and redox activity. • Wireless charging and LEDs illumination demonstrated the practical applicability of the assembled supercapacitor. The rational design of electrode architectures is critical for developing high-performance supercapacitors with efficient charge storage and practical energy applications. Herein, a diatomite (De) templated NiO/NiS 2 composite electrode (NiO/NiS 2 -etch) with a distinctive layered nanosheet/nanosphere architecture was constructed through a controllable partial sulfurization strategy. By regulating the NiO@De and TAA ratio to 2:1, partial conversion of NiO nanosheets into NiS 2 nanospheres was achieved, while the three-dimensional hollow porous framework of diatomite was effectively preserved. The resulting layered structure provides abundant electrolyte-accessible active sites and promotes rapid charge transfer within the electrode. Benefiting from this structural design, the NiO/NiS 2 -etch electrode delivers a high specific capacitance of 1020 F/g at 1 A/g and retains 80.52% of its capacitance after 5000 charge–discharge cycles. Furthermore, the assembled supercapacitor was integrated into a wireless charging system, where the stored energy was successfully utilized to activate LED indicators, demonstrating the capability of supercapacitors as efficient energy storage units for wireless charging applications. This work presents a controllable biomass template strategy for constructing layered composite electrodes and provides new insights into the development of supercapacitor-powered wireless energy technologies. Download: Download high-res image (214KB) Download: Download full-size image