Thermodynamic and kinetic insights for manipulating aqueous Zn battery chemistry: Towards future grid-scale renewable energy storage systems

The invention of aqueous Zn batteries (AZBs) traces back to the eighteenth century. Recently, however, AZBs have been undergoing a renaissance due to the urgent need for renewable energy storage devices that are intrinsically safe, inexpensive, and environmentally benign. The escalating demand for high-energy, fast-charging AZBs, particularly in grid-scale energy storage systems, necessitates a profound exploration of the fundamental aspects of electrode chemistries. In particular, a comprehensive understanding from the viewpoints of thermodynamics and kinetics is crucial, with the aim of advancing the development of next-generation AZBs that have high power and energy densities. However, clarification about the fundamental issues in AZB chemistry has yet to be achieved. This review offers a thorough exploration of the thermodynamics and dynamic mechanisms at the anode and cathode, with the aim of helping researchers achieve high-performance AZBs. The inherent challenges and corresponding strategies related to electrode thermodynamic and dynamic optimization are summarized, followed by insights into future directions for developing high-energy, fast-charging AZBs. We conclude by considering the future prospects for AZBs and offering recommendations for making further advancements in discovering new redox chemistries, optimizing electrode architectures, and achieving integrated battery designs, all of which are considered essential and time-sensitive for making high-energy, fast-charging, and durable AZBs a reality.