Bipolar BINOL–PIM Cathode for High-Performance Aluminum Batteries

Given the high abundance of aluminum in the Earth's crust, the development of aluminum-ion batteries can provide a cost-effective solution for large-scale energy storage. However, the key challenge in this field is to identify high-quality cathode materials that enable effective insertion/extraction of aluminum complex ions. In this regard, we present a strategy to prepare high-capacity, long-cycling aluminum-ion batteries aluminum–ion batteries (ALBs) cathode materials. High capacity was achieved by introducing multiple active sites into a 1,1′-bi-2-naphthol (BINOL) polymer of intrinsic microporosity cathode material to realize dual aluminum complex ion adsorption. The cathode had adjustable mesoporous structure that enabled its activation, wherein the pore size gradually increased during the insertion/extraction of aluminum complex ions, effectively enhancing battery capacity and cycling stability. The aluminum-ion battery cathode material achieved a high capacity of up to 110 mAh/g at a current density of 200 mA/g and could withstand over 3000 cycles at a high current density of 1 A/g. These findings provide a design approach for aluminum-battery cathode materials intended for low-cost, large-scale energy storage.