Flexible and weavable secondary Zn-MnO2 batteries derived from cellulose of Juncus effusus

Abstract

To keep pace with the fast development of portable and wearable electronics, considerable public and scientific attentions have been paid to the flexible energy storage devices with characteristics of light weight, low cost and high electrochemical performance. In this work, we demonstrate a feasible strategy to fabricate novel strand-shaped electrodes from the biomass of Juncus effusus (JE), which can be easily integrated into flexible and rechargeable Zn-MnO₂ batteries with high electrochemical performance. Notably, JE has a very unique three dimensional (3D) triangular-like hollow network microstructure, which greatly favors active material loading, charge transfer and ion diffusion. The obtained aqueous battery presents an excellent specific capacity of 325 mAh g⁻¹ at the current density of 0.3 A g⁻¹, as well as stunning cycling stability for up to 4000 cycles with 127.53 % retention of the initial capacity. Remarkably, when assembled with a gel electrolyte, the quasi-solid-state battery can work normally under various extreme conditions, including bending, hammering, burning, soaking and puncturing. In addition, due to the high flexibility, the electrodes can be woven in parallel into a textile to form an energy supply unit and successfully power an electronic watch, demonstrating high potential of JE in the fabrication of flexible energy storage devices.