2025 AIChE Annual Meeting

Influence of Manganese Dioxide Polymorphs on the Stability of Lithium-Ion Batteries

Developing a stable and economical cathode material is essential for further advancement in secondary battery technology. While lithium-ion batteries dominate the commercial battery market for its high energy density1, its limitation of gas evolution from side reactions of the electrolyte still remains2. To prevent thermal runaway caused by gassing within the cell, the cathode should be stable to ensure the safety and performance of lithium-ion batteries. Manganese dioxide (MnO2) is a promising cathode candidate due to its high theoretical specific capacity and earth abundance3. Moreover, MnO2 exists in polymorphs with varying crystal structures such as tunnel, layered and spinel: each exhibiting different properties4.

Acknowledging that different crystal structures can be used for distinct applications, this study aims to understand the effects of MnO2 polymorphs on electrochemical properties and stability of lithium-ion batteries. While initially the focus of the study was on exploring tunnel sizes of MnO2 polymorphs and their effects on lithium-ion intercalation, we observed varying amounts of cell gassing for each crystal structure. This suggested there are other factors within the MnO2 polymorph that may affect its properties. As previous literature has shown correlation between band gap energy and surface reactivity of other metal-oxides5, this study will center on surface reactions of oxygen in MnO2 polymorphs that lead to CO2 and H2 gassing by using Differential Electrochemical Mass Spectrometry (DEMS). Furthermore, we seek to assess the structural integrity of our cathode materials by identifying phase transformations under long-term cycling. By computing the surface area and band gap energy analysis of each polymorph, we aspire to investigate the association between surface reactivity of MnO2 and its stability as a cathode for enhanced safety and performance of commercial lithium-ion batteries.

[1] SAJCE, 50, 2024

[2] J. Energy Storage, 87, 2024

[3] J. EnergyChem, 7(3), 2025

[4] J. Solid State Chem., 305, 2022

[5] J. Phys. Chem., 12, 2021