Tuning effect of vanadium substitution on the structural and electronic properties of potassium hollandite surfaces
Journal Article
·
· Journal of Chemical Physics
- Stony Brook Univ., NY (United States)
- Brookhaven National Laboratory (BNL), Upton, NY (United States)
- Stony Brook Univ., NY (United States); Brookhaven National Laboratory (BNL), Upton, NY (United States)
Metal oxide surfaces possess unique properties that are crucial for a wide variety of applications. Herein, density functional theory calculations are performed to study surfaces of potassium hollandite, KMn8O16, a promising cathode material for electrochemical energy storage, and the vanadium-substituted analog KMn7VO16. The results show that there is a clear increase in the stability of KMn8O16 with (001) < (110) < (100) or (010), apt to adopt an elongated rod-like morphology. The vanadium (V)-substitution lowers the crystal symmetry and prefers to occupy the surface sites, resulting in electron redistribution and selective tuning of surface energy depending on the surface structures. In particular, the higher stability of substituted V4+ compared with Mn4+ ions leads to stabilization of the (001) surface due to the direct interaction of reduced Mnδ+ ions on the surface, while such tuning effect decreases with the increase in surface stability, (110) > (100) and (010). As a result, the KMnO16 rod is shortened upon V-substitution as observed experimentally, effectively facilitating the ion transport during discharge. The V substituents also introduce stabilization to the defect surfaces resulting from Mn2+ dissolution during cycling, thereby hindering further structural decay. In conclusion, our study demonstrates the potential tuning effect of V-substitution to promote the ion transport and mitigate the capacity degradation of α-MnO2-based materials.
- Research Organization:
- Brookhaven National Laboratory (BNL), Upton, NY (United States)
- Sponsoring Organization:
- National Science Foundation (NSF); USDOE Office of Science (SC), Basic Energy Sciences (BES)
- Grant/Contract Number:
- SC0012673; SC0012704
- OSTI ID:
- 3008060
- Report Number(s):
- BNL--229190-2025-JAAM
- Journal Information:
- Journal of Chemical Physics, Journal Name: Journal of Chemical Physics Journal Issue: 20 Vol. 163; ISSN 1089-7690; ISSN 0021-9606
- Publisher:
- American Institute of Physics (AIP)Copyright Statement
- Country of Publication:
- United States
- Language:
- English
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