Enhanced Structural Stability of Nickel-Cobalt Hydroxide via Intrinsic Pillar Effect of Metaborate for High-Power and Long-Life Supercapacitor Electrodes

Layered alpha-Ni(OH)(2) and its, derivative bimetallic hydroxides (e.g., alpha-(Ni/Co)(OH)(2)) have attracted much attention due to their high Specific capacitance, although their insufficient cycling stability has blocked their wide application in various technologies. In this work; we demonstrate that the cycling performance of alpha-(Ni/Co)(OH)(2) can be obviously enhanced via the intrinsic pillar effect of metaborate. Combining the high porosity feature of the metaborate stabilized alpha-(Ni/CO)(OH)(2) and the improved electronic conductivity Offered by graphene substrate, the average capacitance fading rate of the metaborate stabilized alpha-(Ni/Co)(OH)(2) is only similar to 0.0017% per cycle within 10 000 cycles at the current density of 5 A g(-1). The rate performance is excellent over a wide temperature range from -20 to 40 degrees C. We believe that the enhancements should mainly be ascribed to the excellent structural stability offered by the metaborate pillars, and the detailed mechanism is discussed.