A reliable gel polymer electrolyte enables stable cycling of rechargeable aluminum batteries in a wide-temperature range

Abstract

Rechargeable aluminum batteries are regarded as one of the most promising candidates for post-lithium energy storage systems due to the low cost and high capacity of aluminum metal. However, the current ionic liquid electrolyte of rechargeable aluminum batteries are facing several critical issues including moisture sensitivity, electrolyte leakage and corrosivity, which would substantially undermine Coulombic efficiency and cycling stability. Herein, a polyamide (PA, nylon)-based gel polymer electrolyte in which the ionic liquid is trapped into the polyamide matrix is prepared through a facile process. The strongly hydrogen-bonded PA macromolecular chains are first unwound in the acidic ionic liquid under the conditions of stirring and heating and then reorganize into an association-linked configuration when cooling. This PA-based gel polymer electrolyte (PAGPE) demonstrates improvements of moisture sensitivity, electrolyte leakage and corrosivity compared to the ionic liquid electrolyte. The assembled Al/graphite battery with PAGPE electrolytes works well in a wide temperature range from −30 °C to 45 °C. This work provides a promising strategy for promoting the developments of rechargeable aluminum batteries.