Rechargeable Li/Cl₂ Battery Down to-80 C

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 degrees C, employing Li metal negative electrode, a novel carbon dioxide (CO2) activated porous carbon (KJCO(2)) as the positive electrode, and a high ionic conductivity (approximate to 5-20 mS cm(-1) from -80 degrees C to room-temperature) electrolyte comprised of aluminum chloride (AlCl3), lithium chloride (LiCl), and lithium bis(fluorosulfonyl)imide (LiFSI) in low-melting-point (-104.5 degrees C) thionyl chloride (SOCl2). Between room-temperature and -80 degrees C, the Li/Cl-2 battery delivers up to approximate 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 degrees C, Cl-2/SCl2/S2Cl2 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 approximate to 4 V with up to approximate to 1000 mAh g(-1) capacity for SCl2/S2Cl2 reduction and up to approximate to 4000 mAh g(-1) capacity at approximate to 3.1 V plateau for Cl-2 reduction.