Controllable synthesis of Ni1-xCoxMoO4 with tunable morphologies for high-performance asymmetric supercapacitors

Recently, elemental doping has proven to be an efficient method to improve the electrochemical performance of nanomaterials. In this work, we successfully synthesized Ni1-xCoxMoO4 with tunable morphologies through Co-doping by a facile chemical co-precipitation method, among which Ni0.85Co0.15MoO4 displays an excellent specific capacitance (1301 F g−1 at 1 A g−1), which is higher than NiMoO4 electrode (1050.4 F g−1 at 1 A g−1) and Ni0.7Co0.3MoO4 electrode (755.2 F g−1 at 1 A g−1). In addition, Ni0.85Co0.15MoO4 electrode shows excellent cycling stability with 86% retention of its original capacitance after 3000 cycles. Additionally, an asymmetric supercapacitor (ASC) device can be fabricated using Ni0.85Co0.15MoO4/nickel foam (Ni0.85Co0.15MoO4/NF) as positive electrode and active carbon/nickel foam (AC/NF) as negative electrode. The as-fabricated ASC achieves a high energy density of 37.26 Wh kg−1 at the power density of 400 W kg−1, highlighting its potential application for the efficient energy storage devices.