Energy Storage Science and Technology ›› 2022, Vol. 11 ›› Issue (5): 1401-1410.doi: 10.19799/j.cnki.2095-4239.2021.0580

• Energy Storage Materials and Devices • Previous Articles     Next Articles

Development status and future prospects of flexible metal-air batteries

Zhicheng CHEN(), Zongxu LI, Ling CAI, Yisi LIU()   

  1. Hubei Normal University, Huangshi 435002, Hubei, China
  • Received:2021-11-04 Revised:2022-01-05 Online:2022-05-05 Published:2022-05-07
  • Contact: Yisi LIU E-mail:czc420321@foxmail.com;yliu88@hbnu.edu.cn

Abstract:

A flexible metal-air battery is paid lots of attention because of flexible deformation and energy storage. At present, flexible metal-air batteries are still beset by a host of problems, including battery flexibility, low conductivity and flexibility in air electrodes, and low ionic conductivity and poor mechanical properties in solid gel electrolytes. This review summarizes the structural classification of the main types of flexible metal-air batteries: one-dimensional cable-type, two-dimensional planar-type, and three-dimensional sandwich-structure type. Next, the paper examines the preparation and characteristics of non-free-standing and free-standing air electrodes. Non-free-standing electrodes are prepared using a binder to coat the catalyst onto a conductive substrate (e.g., carbon paper or cloth). Binder additives have disadvantages: they increase the inactive material content, block the pore structure, reduce electrical conductivity, and allow the catalyst to flake off. In contrast, free-standing electrodes use hydrothermal vapor-phase atomic layer deposition to grow catalysts in situ on conductive substrates. This avoids the problems noted above for non-free-standing electrodes. This review goes on to summarize related research into improving electrolyte performance and ionic conductivity (by adding different polymers, reducing polymer crystallinity, and through temperature changes). Finally, the outlook for future development of metal-air batteries is explored. Preparation of free-standing electrodes and investigation of new gel electrolyte materials are expected to become research hotspots. If the interface between air electrode and gel electrolyte can be brought into closer contact, leading to integration, the battery could be started directly by dripping electrolyte and adding metal foil. This would greatly simplify assembly and extend the potential applications of flexible metal-air batteries.

Key words: flexible metal-air batteries, cathode, free-standing, gel electrolyte

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