Controlled synthesis of uniform porous CuO microspheres for enhanced sodium storage

Abstract

Uniform porous CuO microsphere is prepared by a precipitation method, followed by calcination in air. When their electrochemical properties were evaluated by testing Na half-cells, the resultant sample, calcined at 400 °C, can deliver initial discharge and charge capacities of 704.5 and 439.7 mA h g−1 at 100 mA g−1 respectively. After the 50th cycle, discharge capacity is 284.3 mA h g−1, which corresponds to 62.79% of the 2nd discharge capacity. Such excellent performance is attributed to the formation of mesopores, nanoparticles, and large specific surface area of the CuO microsphere, which can effectively reduce the ionic diffusion distance and ensure high electronic mobility among particles.