# Perspective on Aqueous Batteries: Historical Milestones and Modern Revival

## TL;DR

Aqueous batteries are being revived for safe, low-cost energy storage after being overshadowed by lithium-ion batteries.

## Contribution

The paper provides a historical and modern analysis of aqueous batteries to guide future research and applications.

## Key findings

- Aqueous batteries can now offer extended voltage windows and improved cycling stability.
- They are best suited for grid-scale and decentralized energy systems due to safety and cost advantages.
- Modern advances in electrolyte and electrode design have made aqueous batteries more viable.

## Abstract

Aqueous batteries have played a pivotal yet fluctuating role in the evolution of electrochemical energy storage. From their foundational success in lead–acid and nickel‐based chemistries to their eclipse by lithium‐ion batteries, aqueous systems were long regarded as technologically inferior due to limited energy density and poor cycling stability. However, the urgent demand for safe, low‐cost, and sustainable storage has sparked a renaissance, fueled by breakthroughs in electrolyte engineering and advanced electrode materials for both anodes and cathodes. This review revisits the historical trajectory of commercialized aqueous batteries, extracting lessons from past successes and failures while highlighting the technological advances that now enable extended voltage windows, improved cycling stability, and scalable manufacturing. We argue that the future of aqueous batteries lies not in directly competing with lithium‐ion in high‐energy applications, but in complementing them across grid‐scale storage, uninterruptible power supplies, and decentralized energy systems where safety, cost, and recyclability are paramount. By connecting history with current progress, we reflect on how these insights reshape expectations for the next generation of aqueous batteries and their role in a more diversified and sustainable energy storage landscape.

This review retraces the development of aqueous batteries from classical Zn‐MnO2 chemistry to modern Zn and Ni systems, correlating voltage, capacity, and electrolyte formulation with practical performance. By mapping historical success and failure onto current and future research directions, it identifies guiding principles that steer the design of safe, low‐cost, and application‐oriented aqueous energy storage.