The effects of vanadium substitution on one-dimensional tunnel structures of cryptomelane: Combined TEM and DFT study
- Brookhaven National Lab. (BNL), Upton, NY (United States)
- Stony Brook Univ., NY (United States). Dept. of Chemistry
- Brookhaven National Lab. (BNL), Upton, NY (United States); Stony Brook Univ., NY (United States). Dept. of Chemistry
- Brookhaven National Lab. (BNL), Upton, NY (United States); Stony Brook Univ., NY (United States)
Rational design of energy storage materials requires mechanistic understanding which relies on atomic scale characterization of structure and defects. In this paper we utilize vanadium (V)-substituted one-dimensional cryptomelane as a model material to study structural features critical to electrochemical reversibility of the cathode in lithium-ion batteries. We found the substitution of manganese (Mn) atoms in the tunnel wall with V enhances structural uniformity in the parent KMn8O16 material by inhibiting formation of irregular (2 × 3 and 2 × 1) manganese oxide tunnel structures. Upon lithiation, both transmission electron microscopy (TEM) and density functional theory (DFT) reveal significant structural evolution, eventually resulting in phase separation and formation of highly reduced manganese oxide. During this process, Mn4+ accepts electrons donated by intercalated Li, while the V4+ substituent is not electrochemically reduced but acts to stabilize the tunnel framework structure. As a result, the V substituted material shows higher operating voltage and improved electrochemical reversibility. Our results highlight the benefits of V-substitution in cryptomelane, and the significance of integrating characterization with simulation for understanding and developing design principles for lithium ion battery materials.
- Research Organization:
- Energy Frontier Research Centers (EFRC) (United States). Center for Mesoscale Transport Properties (m2mt); Brookhaven National Laboratory (BNL), Upton, NY (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC), Basic Energy Sciences (BES); National Science Foundation (NSF)
- Grant/Contract Number:
- SC0012704; SC0012673; 1839287
- OSTI ID:
- 1633871
- Alternate ID(s):
- OSTI ID: 1599463
- Report Number(s):
- BNL-216062-2020-JAAM
- Journal Information:
- Nano Energy, Vol. 71, Issue C; ISSN 2211-2855
- Publisher:
- ElsevierCopyright Statement
- Country of Publication:
- United States
- Language:
- English
Web of Science
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