Progress in Rechargeable Aqueous Zinc- and Aluminum-Ion Battery Electrodes: Challenges and Outlook

Modern cities demand a reliable supply of electricity when and where it is needed, therefore a key design for power generators feeding on noncontinuous, nonfuel renewables is installing auxiliary battery-type energy storage systems (BESS). Batteries using Zn ions or Al ions in aqueous electrolytes are highly attractive due to low cost and elemental abundance considerations, but attaining reversibility at a high energy density and long-life operation is challenging. Here, the authors review recent reports of reversible aqueous-electrolyte batteries, focusing on how mechanisms of electrochemical activation, insertion, and conversion occur. Further, key issues related to cation mobility, electrode stability, the formation of electrode-electrolyte interface, and electrolyte decomposition, along with possible solutions or research directions for enabling superior performance of aqueous Zn-ion batteries and Al-ion batteries are explored.