Homogeneous alloying reaction via self-assembly strategy for high-areal-density dual-ion batteries

Dual-ion battery (DIB) has sparked growing interest in recent years due to its high working voltage, low cost, and eco-benignity. However, the reported low areal density of cathode (< 2.5 mg cm-2) leads to low energy density, far from commercial application. Besides, alloying-type anodes such as aluminum (Al) with high theoretical capacity suffer from uneven alloying reaction and remarkable volume change during cycling, especially when matched with high areal-density cathode. Herein, we introduce a facile interface engineering strategy, namely self-assembly of graphite oxide (GO) on an Al foil anode with further pre-lithiation to redistribute Li+ ions and render a uniform alloying reaction. This strategy can effectively decrease the transfer barrier of Li+ ions and inhomogeneous hot spots on the surface of the Al anode. Consequently, when paired with an expanded graphite cathode with high-areal-density (10.2 mg cm-2), the modified Al anode exhibits much improved structural stability. The assembled DIB exhibits good cycling stability with high capacity retention of 95.5% over 200 cycles. Moreover, the DIB with high areal density achieves high energy density of up to -176 Wh kg-1 based on the total mass of electrode materials and electrolyte, which is among the best values of reported DIBs to date.

Automated summary

By self-assembling graphite oxide on the aluminum anode and pre-lithiating it, the redistribution of Li+ ions and reduction of transfer barrier and inhomogeneous hot spots can be achieved, resulting in improved cycling stability and energy density of the dual-ion battery.