Layered cobalt nickel silicate hollow spheres as a highly-stable supercapacitor material

• Layered cobalt nickel silicate hollow nanospheres were prepared for by a facile hydrothermal method.
• The mechanism of the layered cobalt nickel silicate hollow nanospheres growth was investigated.
• The prepared material exhibited specific capacitance and outstanding long-term cycling stability.

Among the actively studied electrode materials, layered cobalt or nickel compounds have been recognized as a family of promising electrode materials for supercapacitor. However, the cycling performance of these materials is unsatisfactory by far. In this work, a novel and stable layered cobalt nickel silicate hollow sphere compound was prepared for supercapacitor application using a facile hydrothermal synthetic approach. The obtained material exhibited a good specific capacitance and outstanding long-term cycling stability (only 0.7% and 5% losses of its initial specific capacitance after 10,000 and 20,000 cycles, respectively) at a high current density of 20 A/g after annealing at 600 °C. This work provides new insights of designing novel cobalt or nickel compounds for supercapacitor with excellent stability, and promotes the application of layered metal silicates as advanced supercapacitor materials.