Hygroscopic Chemistry Enables Fire‐Tolerant Supercapacitors with a Self‐Healable “Solute‐in‐Air” Electrolyte
Huarong Xia, Zhisheng Lv, Wei Zhang, Jiaqi Wei, Lin Liu, Shengkai Cao, Zhiqiang Zhu, Yuxin Tang, Xiaodong Chen
Abstract
Abstract High‐temperature‐induced fire is an extremely serious safety risk in energy storage devices; which can be avoided by replacing their components with nonflammable materials. However; these devices are still destroyed by the high‐temperature decomposition; lacking reliability. Here, a fire‐tolerant supercapacitor is further demonstrated that recovers after burning with a self‐healable “solute‐in‐air” electrolyte. Using fire‐tolerant electrodes and separator with a semiopen device configuration; hygroscopic CaCl 2 in the air (“CaCl 2 ‐in‐air”) is designed as a self‐healable electrolyte; which loses its water solvent at high temperatures but spontaneously absorbs water from the air to recover by itself at low temperatures. The supercapacitor is disenabled at 500 °C; while it recovers after cooling in the air. Especially; it even recovers after burning at around 647 °C with enhanced performance. The study offers a self‐healing strategy to design high‐safety; high‐reliability; and fire‐tolerant supercapacitors; which inspires a promising way to deal with general fire‐related risks.