Flexible Aqueous Capacitors Based On SiC-boron-doped Graphene And Core-shell SiC@graphene

Flexible aqueous pseudocapacitors have the advantages of high specific capacitance,high safety,low cost,and fast ion diffusion.However,the development of such devices is a challenge because of the low stability of the active material and the high interface resistance of the current collector-active material.In this study,we used silicon carbide（SiC）-boron-doped graphene（BGr）nanosheets and core-shell SiC@Gr nanoparticles as the cathode and anode,respectively,and constructed a flexible aqueous asymmetric capacitor（ASC）with a 3M Na OH/carboxymethyl cellulose hydrogel as the electrolyte.In an aqueous Na OH solution,the optimized SiC-BGr cathode showed a specific capacitance of 1384.3 m F cm^-2(461.4 F g^-1)at the current density of 3 m A cm^-2(1 A g^-1),and the core-shell SiC@Gr anode showed a wide potential window of-1.0–0 V.The as-assembled ASC device had a high working voltage of 1.4 V,delivered an excellent capacitance of 337.1 m F cm^-2,and retained86%of its initial capacitance after 10?000 cycles.Furthermore,the ASC also showed high energy density(57.3μWh cm^-2),high power density(6536.9μW cm^-2),high bending stability,and applicability at a low temperature of-20°C.Thus,the preparation of novel SiC-Gr materials can promote the development of flexible aqueous capacitors with high working voltage and good temperature adaptability for application in the field of wearable electronic devices with safety,strong environmental adaptability,and reliable performance.