Xiaodan Huang, Yang Liu, Hongwei Zhang, Jun Zhang, Owen Noonan, Chengzhong Yu*

 

Australian Institute for Bioengineering and Nanotechnology,
The University of Queensland,
Brisbane QLD 4072, Australia

 

Aluminum-ion battery (AIB) is emerging as an attractive new electrical energy storage system. Despite of the recent breakthroughs in AIB technology, state-of-the-art cathode materials suffer from mediocre volumetric capacity (~0.74 mAh cm-3) and AIB in the widely-used coin-cell configuration is rarely reported. Here we present the synthesis of free-standing monolithic nanoporous graphene foam with a high density and a new strategy to stabilize coin-cell type AIB. A new AIB cathode material with significantly improved volumetric capacity and high gravimetric capacity has been developed. Free-standing monolithic nanoporous graphene foam with well-defined nanopores (94.2 nm), high surface area (762 m2 g-1), large pore volume (2.45 cm3 g-1) and improved weight density (81.0 mg cm-3) has been produced by a hydrothermal hard-templating approach and in-situ hydrophobicity induced silica/GO self-assembly. A new coin-cell based AIB configuration has also been developed by applying conductive polymer PEDOT coating to prevent the corrosion. With our design, free-standing NGF has demonstrated promising electrochemical performances, including significantly improved volumetric capacities up to 12.2 mAh cm-3 together with a high gravimetric capacity (up to 151 mAh g-1), and good low temperature property. This novel cathode material and the novel cell configuration present new opportunities for the advancement of AIB.

Figure 1. The correlation between theoretical weight density and pore diameter of highly porous graphene foam at a fixed surface area of 762 m2 g-1 (see discussion in supplementary information). Inset is the illustration of the application of free-standing monolithic NGF cathode in a coin-cell type AIB.