Dense integration of graphene paper positive electrode materials for aluminum-ion battery.

Although Al-ion battery is attracting researchers' attention worldwide, its volumetric energy density was not so promising due to low density of graphite-based positive electrodes in the current published literatures. Thus, defect-free yet densely packed graphene electrodes with high electronic conductivity and fast ionic diffusion are crucial to the realization of compacted Al-ion batteries with high volumetric energy density. In the present work, a self-supported and defect-free graphene-positive electrode (R_HG-P-2850) was successfully produced by a hydriodic acid reduction of the graphene oxide (GO) method, followed by an ultrahigh temperature (2850 °C) annealing treatment. The density of the R_HG-P-2850 (0.32 g cm⁻³) is currently the highest positive electrode material in the preparation of graphene-positive electrodes from GO. R_HG-P-2850 positive electrode enables to deliver considerably high specific capacity 27.1 mAh cm⁻³ (85 mAh g⁻¹) at the current density 2 A g⁻¹. More importantly, a remarkably stable performance was achieved with 20% fading over 8000 cycles. The results enlighten and promote the design and preparation of densely packed graphene-positive electrode to develop high-performance Al/graphene battery. [ABSTRACT FROM AUTHOR]