DOE OSTI · 2584429
Interface‐Controlled Redox Chemistry in Aqueous Mn 2 ⁺/MnO₂ Batteries
Abstract
Manganese dioxide (MnO 2 ) deposition/dissolution (Mn 2+ /MnO 2 ) chemistry, involving a two-electron-transfer process, holds promise for safe and eco-friendly large-scale energy storage. However, challenges like electrode/electrolyte interface environment fluctuations (H + and H 2 O activity), irreversible Mn degradation, and limited understanding of degradation mechanisms hinder the reversibility of the Mn 2+ /MnO 2 conversion. This study demonstrates a vanadyl/pervanadyl (VO 2+ /VO 2 + ) redox-mediated interface designed for high-energy Mn 2+ /MnO 2 batteries. Unlike flow systems, this work uncovers, for the first time, the mechanism of a static redox-mediated interface in regulating interfacial H + and H 2 O activities. Significantly, the VO 2+ /VO 2 + chemical redox mediation targets Mn 3+ intermediates, suppressing their hydrolysis and enabling 100% Mn 2+ /MnO 2 conversion. The redox-mediated interface enhances the Mn redox electron transfer process, achieving a stable ≈95% coulombic efficiency and ultrahigh capacity of 100 mAh cm −2 with an areal energy density of 111 mWh cm −2 , outperforming flow systems. The electrode also exhibits an average specific capacity of 593 mAh g −1 , approaching the theoretical limit of 616 mAh g −1 , and a specific energy density of 721 Wh kg −1 at high MnO 2 loadings (50–150 mg cm −2 ). Furthermore, the findings highlight the critical role of interfacial redox mediation in regulating H + and H 2 O activities and underscore the significance of interface dynamics.
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Xue, Xinzhe [University of California, Santa Cruz, CA (United States)], Liu, Zhen [University of California, Santa Cruz, CA (United States)], Chandrasekaran, Swetha [Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States)], Eisenberg, Samuel [University of California, Santa Cruz, CA (United States)], Althaus, Curtis [Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States)], Freyman, Megan C. [Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States)], Pinongcos, Anica [University of California, Santa Cruz, CA (United States)], Ren, Qiu [University of California, Santa Cruz, CA (United States)], Valdovinos, Logan [University of California, Santa Cruz, CA (United States)], Hsieh, Cathleen [University of California, Santa Cruz, CA (United States)], Hu, Bintao [University of California, Los Angeles, CA (United States)], Dunn, Bruce [University of California, Los Angeles, CA (United States)], Orme, Christine A. [Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States)], Wang, Xiao [University of California, Santa Cruz, CA (United States)], Worsley, Marcus A. [Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States)], Li, Yat [University of California, Santa Cruz, CA (United States)] (ORCID:0000000280582084). 2025-04-21. Interface‐Controlled Redox Chemistry in Aqueous Mn 2 ⁺/MnO₂ Batteries. https://doi.org/10.1002/adma.202419505
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