Rechargeable Li/Cl<sub>2</sub> Battery Down to −80 °C
Peng Liang, Guanzhou Zhu, Cheng‐Liang Huang, Yuan‐Yao Li, Hao Sun, Bin Yuan, Shu‐Chi Wu, Jiachen Li, Feifei Wang, Bing‐Joe Hwang, Hongjie Dai
Abstract
Abstract Low temperature rechargeable batteries are important to life in cold climates, polar/deep‐sea expeditions, and space explorations. Here, this work reports 3.5–4 V rechargeable lithium/chlorine (Li/Cl 2 ) batteries operating down to −80 °C, employing Li metal negative electrode, a novel carbon dioxide (CO 2 ) activated porous carbon (KJCO 2 ) as the positive electrode, and a high ionic conductivity (≈5–20 mS cm −1 from −80 °C to room‐temperature) electrolyte comprised of aluminum chloride (AlCl 3 ), lithium chloride (LiCl), and lithium bis(fluorosulfonyl)imide (LiFSI) in low‐melting‐point (−104.5 °C) thionyl chloride (SOCl 2 ). Between room‐temperature and −80 °C, the Li/Cl 2 battery delivers up to ≈29 100–4500 mAh g −1 first discharge capacity (based on carbon mass) and a 1200–5000 mAh g −1 reversible capacity over up to 130 charge–discharge cycles. Mass spectrometry and X‐ray photoelectron spectroscopy probe Cl 2 trapped in the porous carbon upon LiCl electro‐oxidation during charging. At −80 °C, Cl 2 /SCl 2 /S 2 Cl 2 generated by electro‐oxidation in the charging step are trapped in porous KJCO 2 carbon, allowing for reversible reduction to afford a high discharge voltage plateau near ≈4 V with up to ≈1000 mAh g −1 capacity for SCl 2 /S 2 Cl 2 reduction and up to ≈4000 mAh g −1 capacity at ≈3.1 V plateau for Cl 2 reduction.