High performance carbon-coated hollow Ni12P5 nanocrystals decorated on GNS as advanced anodes for lithium and sodium storage

Abstract

Transition-metal phosphides have been considered as promising anode materials for rechargeable secondary batteries owing to their low cost and high capacity. However, low electronic conductivity and poor stability limit their further development. Herein, we have designed a template-free refluxing method for synthesizing tailored carbon-coated hollow Ni₁₂P₅ nanocrystals in situ grown on reduced graphene oxide nanosheets (denoted as Ni₁₂P₅@C/GNS). The hollow structure can accommodate volume expansion and shorten the ion transfer path. The GNS loading and carbon shell can efficiently prevent Ni₁₂P₅ from aggregating and improve the electronic conductivity. As an anode of Li-ion batteries (LIBs), the hollow Ni₁₂P₅@C/GNS composite displays an excellent discharge specific capacity of 900 mA h g⁻¹ at a current density of 100 mA g⁻¹ after 100 cycles and outstanding rate capability. Furthermore, it also shows a good Na storage capability with a reversible capacity of 235 mA h g⁻¹ at 100 mA g⁻¹. Therefore, our work demonstrates that this hollow Ni₁₂P₅@C/GNS composite has great potential for Li/Na storage.