Enabling Rechargeability in Metal–Chlorine Batteries: The Critical Roles of Cathodes and Electrolytes

Metal–chlorine batteries, including Li-Cl2, Na-Cl2 and Ca-Cl2 systems, have emerged as promising energy storage technologies in recent years, delivering impressive performance in terms of reversible capacity (up to 5000 mAh g−1), current density (up to 16,000 mA g−1), cycle life (up to 500 cycles) and low-temperature operation (down to −80 °C). The critical roles of cathodes and electrolytes, enabling the birth and performance enhancement of metal–chlorine batteries, are highlighted and discussed here, providing an overview of current research progress on metal–chlorine batteries at the same time. Finally, we demonstrate a forward-looking view of where metal–chlorine batteries are headed.