Chloride ion battery: A new emerged electrochemical system for next-generation energy storage

In the scope of developing new electrochemical concepts to build batteries with high energy density, chloride ion batteries (CIBs) have emerged as a candidate for the next generation of novel electrochemical energy storage technologies, which show the potential in matching or even surpassing the current lithium metal batteries in terms of energy density, dendrite-free safety, and elimination of the dependence on the strained lithium and cobalt resources. However, the development of CIBs is still at the initial stage with unsatisfactory performance and several challenges have hindered them from reaching commercialization. In this review, we examine the current advances of CIBs by considering the electrode material design to the electrolyte, thus outlining the new opportunities of aqueous CIBs especially combined with desalination, chloride redox battery, etc. With respect to the developing road of lithium ion and fluoride ion batteries, the possibility of using solid-state chloride ion conductors to replace liquid electrolytes is tentatively discussed. Going beyond, perspectives and clear suggestions are concluded by highlighting the major obstacles and by prescribing specific research topics to inspire more efforts for CIBs in large-scale energy storage applications.