Construction of Bimetallic Nickel Cobalt Selenides Pompon as Superior Anode for High Performance Sodium Storage
Sodium-ion batteries are considered to be one of the most ideal alternatives to lithium-ion batteries as the next generation of advanced batteries due to their wide resource and low cost advantages. However, it is urgent to find a suitable anode material to fill the gap due to the fact that the commercial graphite anode cannot be applied to the sodium ion battery. Bimetallic selenides stand out among multitudinous anode materials on account of their synergistic effects and rich electronic reaction processes. Here, nickle cobalt selenides pompon have been successful prepared via a simple solvothermal method. The pompon-like NiCo2Se4 not only promotes the penetration of the electrolyte but also increases the electron and ion diffusion channels. Meanwhile, this design can effectively alleviate the volume expansion of the material during charging and discharging. More importantly, the synergistic effect of Ni and Co bimetals can greatly enrich the electronic reaction process and improve the conductivity to obtain sufficient sodium ion storage. When applying the material as anode of sodium ion batteries, these unique advantages together facilitate NiCo2Se4 to delivers a impressive reversible capacity of 230 mAh g-1 at 5 A g-1 and excellent cycling performance up to 2,500 cycles with a capacity decay rate of only 0.019%.