Rechargeable aluminum-ion batteries (AIBs) have been intensively studied over past years. However, its commercialization is still hindered by the relatively high capital cost. Increasing the specific areal capacity (mAh cm–2) by using a high mass loading of active material in thick electrodes is an effective strategy to decrease the battery cost. Unfortunately, the high viscosity and low ionic conductivity of the ionic liquid electrolytes prevent implementation of this strategy. Herein, the use of semisolid electrodes in AIBs is for the first time proposed to (i) address the poor wettability related to high viscosity and (ii) increase mass transport through thick electrodes limited by the low ionic conductivity. Indeed, specific areal capacities of up 7 mAh cm–2 are achieved in this work, compared to 0.5–1.5 mAh cm–2 as state-of-the-art. This innovative concept is potentially implementable to advanced material designs to achieve improved battery performance in the future.
