Highly Conductive and Reusable Electrolyte Based on Sodium Polyacrylate Composite for Flexible Al-Air Batteries

Abstract

The increasing interests in flexible and wearable electronics stimulates the exploration of new energy storage systems. Flexible aluminum-air batteries with the features of high energy density, good safety, low cost and eco-friendly have attracted much attention. Herein, a sodium polyacrylate (PANa) based electrolyte with an optimized amount of sodium carboxymethyl cellulose (CMC) is prepared through free radical polymerization and employed to fabricate flexible Al-air batteries. The prepared PANa-5%CMC polymer electrolyte exhibits excellent ionic conductivity (0.324 S cm−1), mechanical strength and water uptake ability. This achieved properties can be attributed to the introduce of CMC, which not only decreases size of the pores but also forms the cobweb-like networks with a large amount of functional groups. The fabricated Al-air battery displays good flexibility and shows enhanced discharge performance with a higher voltage plateau and larger specific capacity, resulting in a maximum power density of 137 mW cm−2. More importantly, the used gel polymer electrolyte can be recovered without any performance decay. Furthermore, the Al-air batteries are demonstrated to charge mobile phone and power smart watch in a flexible state, showing promising potential in flexible energy storage devices.