Abstract
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 [SiO4]4- moiety in olivine is desirable. This could allow additional alkali content and hence electron transfer, and increase the capacity. Herein we explore the possibility of a strategy toward new cathode materials and 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 modeling via atomic scale simulation. Transition metal substitution was found to be only favorable for Co, a finding confirmed by the successful solid state synthesis of olivine LixInyCo2-x-ySiO4. Stabilization of the structure was achieved by entropy provided by cation disorder.
| Original language | English |
|---|---|
| Pages (from-to) | 9931-9937 |
| Number of pages | 7 |
| Journal | Inorganic Chemistry |
| Volume | 56 |
| Issue number | 16 |
| DOIs | |
| State | Published - Aug 21 2017 |
Funding
L.F.N. gratefully acknowledges support of the Natural Science and Engineering Council of Canada through funding from the Discovery Grant and Canada Research Chair programs. The authors would like to thank Dr. Ashfia Huq for carrying out neutron diffraction measurements and Dr. Marine Cuisinier for her help in analyzing the XANES data. This research used resources of the Advanced Photon Source an Office of Science User Facility operated for the U.S. Department of Energy (DOE) Office of Science by Argonne National Laboratory and was supported by the U.S. DOE under Contract No. DE-AC02-06CH11357.