Improved-quality graphene film decorated with ultrafine MnO₂ nanoparticles as a multifunctional current collector for high-reversibility zinc-ion batteries

Zinc-ion batteries (ZIBs) are considered as a reasonable alternative to lithium-ion batteries (LIBs) due to their satisfactory safety levels, low cost, and eco-friendliness. Nevertheless, the ZIBs have suffered from rapid capacity fading and unstable cycling stability due to poor reversibility. To overcome this issue, a suitable current collector with high electrical conductivity and good interfacial adhesion to the electrode material is essential. Herein, for the first time, an improved-quality graphene film (IQGF) is uniformly decorated with ultrafine manganese oxide nanoparticles (UFMP) and the resulting UFMP@IQGF composite is used as a multifunctional current collector. The as-fabricated ZIB exhibits a superb energy storage performance and reversibility, with an improved specific capacity of 404.7 mA h g⁻¹ at a current density of 0.1 A g⁻¹, and an excellent ultrafast cycling stability, with a capacity retention of 83.7% for up to 300 cycles at a current density of 2.0 A g⁻¹. Moreover, the all-solid-state ZIB using a gel-electrolyte exhibits a good energy storage performance, mechanical flexibility, and feasibility for practical applications.