Recent developments and future perspectives of anionic batteries

This paper contains a review of developments in anionic batteries. Among the several battery chemistries, Li-ion batteries (LIBs) have excelled in the past two decades. However, new cation based rechargeable battery chemistries of Na+, K+, Mg2+, Ca2+ shuttle have gained interest. Apart from cations, anionic shuttle dependent batteries offer great potential, too. While nickel metal hydride (Ni-MH) and nickel cadmium (Ni-Cd) batteries rely on OH− ion shuttle and are well-studied, commercial anionic batteries, the new members to this family are fluoride-ion batteries (FIBs) and chloride-ion batteries (CIBs). These batteries utilize metal and metal fluoride or metal chloride containing electrodes as source and target of the shuttle ion. The new generation of fluoride-ion, chloride-ion batteries can theoretically offer higher energy densities than LIBs. Herein, we discuss the origin, developments of CIBs, FIBs, and the advancements achieved so far on various electrolytes, cathodes, and anode materials. We will also briefly discuss the status of related aluminium chloride-based, Ni-MH, and Ni-Cd batteries. Overall, this review investigates the progression, state of the art, trends in outcomes, and provides future perspectives, with an anticipating trajectory towards its practical applications.