Stabilization of Lithium Transition Metal Silicates in the Olivine Structure
While olivine LiFePO4 shows amongst the best electrochemical properties of Li-ion positive electrodes with respect to rate behavior owing to facile Li+ migration pathways in the framework, replacing the [PO4] 3- polyanion with a silicate [SO4] 4- moitie in olivine is desirable. This would allow additional balancing alkali content and hence electron transfer, and increase the capacity. We demonstrate the first stabilization of a lithium transition-metal silicate (as a pure silicate) in the olivine structure type. Using LiInSiO4 and LiScSiO4 as the parent materials, transition metal (Mn, Fe, Co) substitutions on the In/Sc site were investigated by computational modelling via atomic scale simulation. Transition metal substitution was found to be only favourable for Co, a finding confirmed by the successful solid state synthesis of olivine LixInyCo2-x-ySiO4. Finally, the stabilization of the structure was achieved by entropy provided by cation disorder.
- Research Organization:
- Argonne National Lab. (ANL), Argonne, IL (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC), Basic Energy Sciences (BES); Natural Science and Engineering Research Council of Canada
- Grant/Contract Number:
- AC02-06CH11357
- OSTI ID:
- 1393479
- Journal Information:
- Inorganic Chemistry, Vol. 56, Issue 16; ISSN 0020-1669
- Publisher:
- American Chemical Society (ACS)Copyright Statement
- Country of Publication:
- United States
- Language:
- English
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