Wearable Bipolar Rechargeable Aluminum Battery

Structural design plays an essential role in the energy density of wearable batteries. Although various flexible materials have been developed to substitute traditional rigid components, current wearable batteries struggle to achieve high energy density because of the excessive inactive components in the traditional monopolar structure. Herein, an all-in-one bipolar Al system is designed as wearable batteries, in which multifunctional carbon/polyethylene film (CPF) serves as the bipolar plate, cell package, and encapsulant. Our designed bipolar Al battery can be designed as a flexible watch strap with a working voltage of 3.21 V and exhibits good capacity retention of 80% under high bending angles (120°), high current densities (960 mA/g), high mass loading (15 mg/cm²), and low temperature (−20 °C). Additionally, as the stack number of cells increasing to five, the volume of traditional serial batteries can nearly halve through bipolar design. It is anticipated that our bipolar configuration concept would offer a new solution for the development of advanced wearable batteries and stimulate the surge of wearable electronics.