Advances in manganese-based cathode electrodes pave the way for next-generation aqueous zinc-ion batteries

As global energy demands rise and environmental concerns intensify, the limitations of traditional lithium-ion batteries—such as resource scarcity, high cost, and safety risks—have prompted the search for safer, cheaper, and more sustainable alternatives. Aqueous zinc-ion batteries (AZIBs) have emerged as a promising solution due to their use of abundant, low-cost, and eco-friendly materials, along with non-flammable aqueous electrolytes that enhance safety. Among various cathode materials explored for AZIBs, manganese-based oxides stand out for their high theoretical capacity, structural versatility, and environmental benignity. However, challenges such as poor cycling stability, limited rate performance, and manganese dissolution have hindered their practical application.

A recent review article published in Frontiers in Energy (2025) by researchers from the University of Shanghai for Science and Technology and Jiangxi University of Science and Technology comprehensively examines the latest advancements in manganese-based cathode materials for AZIBs. The paper systematically explores the electrochemical mechanisms, structural diversity, and performance enhancement strategies of manganese oxides, including ion doping, carbon coating, and electrolyte optimization.

The study identifies four primary energy storage mechanisms in manganese-based AZIBs:

1. Zn²⁺ intercalation/deintercalation
2. Co-intercalation of H⁺ and Zn²⁺
3. Chemical conversion reactions
4. Dissolution–deposition processes

Among the various manganese oxide structures—tunnel-type (e.g., α-, β-, γ-MnO₂), layered (δ-MnO₂), and spinel-type (e.g., ZnMn₂O₄, Mn₃O₄)—each offers unique advantages in terms of ion transport and structural stability. The review highlights that structural engineering, such as morphology control and defect introduction, significantly enhances electrochemical performance.

The authors also emphasize the effectiveness of ion doping—using monovalent (K⁺, Na⁺, NH₄⁺) and multivalent (Co²⁺, Zn²⁺, Mg²⁺, Eu³⁺) cations—to improve conductivity, stabilize crystal structures, and facilitate Zn²⁺ diffusion. Additionally, the integration of metal-organic frameworks (MOFs) and carbon-based materials (e.g., graphene, carbon nanotubes) has been shown to increase surface area, suppress manganese dissolution, and enhance electronic conductivity.

Electrolyte optimization, particularly the formation of stable solid electrolyte interphases (SEIs), is another critical factor in improving battery longevity and suppressing side reactions.

This comprehensive review consolidates recent breakthroughs in manganese-based cathode development for AZIBs and provides a roadmap for future research. By addressing key challenges such as structural degradation, ion diffusion limitations, and interfacial instability, the study lays a solid foundation for the commercialization of high-performance, low-cost, and environmentally friendly aqueous zinc-ion batteries. These advancements could accelerate the adoption of AZIBs in large-scale energy storage and electric mobility applications, contributing to a more sustainable energy future.