Breaking diffusion constraints through fluorine-regulated MnO x /KMnF 3 heterostructures for enhanced aqueous Mg 2+ storage
Year: 2025
Type: article
Abstract: With the continuing demand for clean and sustainable energy storage devices, aqueous magnesium-ion capacitors have gained prominence as a viable electrochemical solution. However, high-performance aqueous magnesium-ion storage devices for energy need to satisfy rigorous requirements due to the large hydrated ionic radius of Mg2+ cations and the structural collapse of host materials during insertion/extraction. Herein, we propose a fluorine-mediated structural regulation strategy to design multivalent manganese oxides (F-m-MnOx) as cathode materials. By partially substituting oxygen sites with fluorine atoms, high-strength Mn-F bonds are formed within the MnO2 lattice, which locally enhance the framework stability by reinforcing the tunnel structure and effectively suppressing structural degradation during cycling. Furthermore, the robust Mn-F bond energy enables a unique “pinning effect” anchoring hydrothermally synthesized KMnF3 nanoparticles onto the MnO2 matrix. These KMnF3 nanoparticles act as dynamic bridges during Mg2+ insertion/extraction processes, with their surface-exposed chemically active sites facilitating transient yet reversible interactions with migrating Mg2+ ions. This innovative design significantly enhances Mg2+ diffusion kinetics through the bulk phase, offering a groundbreaking mechanism to overcome the inherent sluggish ion transport in multivalent cation systems. The F-m-MnOx cathode delivers exceptional performance metrics: a high specific capacity of 142 mAh/g at 0.1 A/g, outstanding cycling stability (89.6% retention after 1800 cycles), and rapid kinetics. This research not only establishes an innovative design concept for advanced electrode materials through halogen-mediated structural engineering but also elucidates the dual magnesium-ion storage mechanism involving both KMnF3 and MnO2 in F-m-MnOx through ex-situ characterization, enabling new possibilities for future clean energy storage.
Source: Nano Research
Authors: Haixi Gu, Siwen Zhang, Minghui Liu, Man Kong, Wenhui Mi, Zhibiao Wang, Hui Li, Hongge Pan, Bosi Yin, Tianyi Ma
Language: English
Subfield: Electrical and Electronic Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $5,290
OpenAlex ID: W4413961178