Bottom‐Up Design of a Green and Transient Zinc‐Ion Battery with Ultralong Lifespan

• Published in: Small (Weinheim an der Bergstrasse, Germany) Germany), 2023-02, Vol.19 (7), p.e2206249-n/a
• Main Authors: Mittal, Neeru, Ojanguren, Alazne, Kundu, Dipan, Lizundia, Erlantz, Niederberger, Markus
• Format: Article
• Language: English
• Subjects: aqueous electrolytes; Batteries; Biocompatibility; Biodegradability; biopolymers; Carboxymethyl cellulose; Composting; Current density; degradation; Electrolytes; Environmental impact; green batteries; hydrogel electrolytes; Hydrogels; Ion currents; Life span; Nanotechnology; Open circuit voltage; Raw materials; Service life; transiency; Zinc; zinc‐ion batteries
• ISSN: 1613-6810; 1613-6829
• DOI: 10.1002/smll.202206249

Transient batteries are expected to lessen the inherent environmental impact of traditional batteries that rely on toxic and critical raw materials. This work presents the bottom‐up design of a fully transient Zn‐ion battery (ZIB) made of nontoxic and earth‐abundant elements, including a novel hydrogel electrolyte prepared by cross‐linking agarose and carboxymethyl cellulose. Facilitated by a high ionic conductivity and a high positive zinc‐ion species transference number, the optimized hydrogel electrolyte enables stable cycling of the Zn anode with a lifespan extending over 8500 h for 0.25 mA cm−2 – 0.25 mAh cm−2. On pairing with a biocompatible organic polydopamine‐based cathode, the full cell ZIB delivers a capacity of 196 mAh g−1 after 1000 cycles at a current density of 0.5 A g−1 and a capacity of 110 mAh g−1 after 10 000 cycles at a current density of 1 A g−1. A transient ZIB with a biodegradable agarose casing displays an open circuit voltage of 1.123 V and provides a specific capacity of 157 mAh g−1 after 200 cycles at a current density of 50 mA g−1. After completing its service life, the battery can disintegrate under composting conditions. A design of a green, fully transient, and high‐performance Zn‐ion battery consisting of a biopolymer hydrogel electrolyte and an organic cathode is presented. With its compostable cell packaging made of agarose, a low contribution of the selected materials to the cradle‐to‐gate environmental impact, this battery represents a significant advancement in the field of transient batteries.