Low-Cost Gel Polymer Electrolyte for High-Performance Aluminum-Ion Batteries

The classical AlCl₃/imidazole-chloride-salt ionic liquid electrolytes are expensive, corrosive, and environmentally sensitive, which limit the large-scale application of aluminum-ion batteries. Herein, a gel polymer electrolyte is prepared through a facile process using a low-cost AlCl₃/Et₃NHCl ionic liquid as the plasticizer and polyamide as the polymer matrix. The gel polymer electrolyte achieves a decent ionic conductivity of 3.86 × 10^-3 S cm^-1, a wide electrochemical stability window of 2.6 V (vs Al), and long-term interfacial stability at room temperature. The assembled Al//graphite battery delivers considerable rate capability and excellent cycling performance. Besides, the gel polymer electrolyte can alleviate both moisture sensitivity and leakage corrosion issues owing to the full encapsulation of the ionic liquid by polyamide polymeric matrix. The gel polymer electrolyte should offer great potential for aluminum-ion battery applications.