Enhanced cyclic stability of Ga2O3@PDA-C nanospheres as pseudocapacitive anode materials for lithium-ion batteries

Abstract

Ga2O3 is widely used as anode material for lithium-ion batteries owing to its high theoretical capacity. However, Ga2O3 has the disadvantages of limited electronic conductivity and severe volume expansion, which seriously restrict its application. Therefore, the Ga2O3 nanospheres were coated with carbon using dopamine hydrochloride as the carbon source, which could self-polymerize along the surface of the Ga2O3 particles, forming a uniform carbon coating layer, resulting in superior overall electrochemical performance. Moreover, this particular pomegranate-like morphology and carbon-coating treatment not only shorten the ion transmission path and improve the cycle stability but also provide abundant lithium-ion storage space inside the particle, which improves the pseudocapacitive storage characteristics. High capacitive contribution ratios were obtained for Ga2O3@PDA-C at different scan rates; these ratios were found to be much higher than those for Ga2O3 electrode at different scan rates; the pseudocapacitance of Ga2O3@PDA-C increased to 69% and the more enormous capacitance contribution indicates its high capacity. Under the synergistic effect of multiple effects, the Ga2O3@PDA-C composite electrode exhibited excellent performance, with an initial capacity of 1863.9 mAh/g and maintained 1059.7 mAh/g after 100 cycles.