Synthesis of amorphous cobalt silicate nanobelts@manganese silicate core-shell structures as enhanced electrode for...

Among diverse transition metal silicates (TMSs), cobalt silicate (Co₂SiO₄) and manganese silicate (MnSiO₃) have been diffusely developed for electrode materials due to their high theoretical capacity, structural stability and simple synthetic process. In this work, Co₂SiO₄ nanobelts@MnSiO₃ have been designed and synthesized as the enhanced electrode for high-performance hybrid supercapacitors. The one-dimensional (1D) Co₂SiO₄ nanobelts enhance their ability to transport electrons along the long axis, which allows current collection during the charge and discharge to improve electrochemical performances. The MnSiO₃ coating can be a steady elastic buffer layer, which can protect the active materials during the charge and discharge in effect. What's more, the "core" and "shell" will both be a considerable offering to the total capacity. Sure enough, the capacitance value of Co₂SiO₄ nanobelts@MnSiO₃ can achieve 309 F g^-1 at 0.5 A g^-1 accompanied by 64% capacitance retention after 10,000 cycles. And the hybrid supercapacitor (HSC) device assembled by Co₂SiO₄ nanobelts@MnSiO₃ and activated carbon (AC) own an excellent capacitance of 384 mF cm^-2 at 2 mA cm^-2 accompanied by 57% capacitance retention after 2000 cycles. Meanwhile, the Co₂SiO₄ nanobelts@MnSiO₃//AC HSC device's power density (P/W m^-2) and energy density (E/Wh m^-2) can reach to be 30 W m^-2 and 0.77 Wh m^-2, respectively. The unique and novel microstructure makes cobalt silicate and manganese silicate shine once again in excellent electrochemical performance.