Journal
CHEMISTRY OF MATERIALS
Volume 26, Issue 2, Pages 1260-1269Publisher
AMER CHEMICAL SOC
DOI: 10.1021/cm403855t
Keywords
-
Funding
- National Science Foundation [1057170]
- EU
- LABEX MUST of Universite de Lyon [ANR-10-LABX-0064]
- U.S. Department of Energy, the Assistant Secretary for Energy Efficiency and Renewable Energy, Office of Vehicle Technologies [DEAC02-98CH10886]
- Direct For Mathematical & Physical Scien
- Division Of Materials Research [1057170] Funding Source: National Science Foundation
- STFC [ST/K00171X/1] Funding Source: UKRI
- Science and Technology Facilities Council [ST/K00171X/1] Funding Source: researchfish
Ask authors/readers for more resources
Li-substituted layered P2-Na-0.80[Li0.12Ni0.22Mn0.66]O-2 is investigated as an advanced cathode material for Na-ion batteries. Both neutron diffraction and nuclear magnetic resonance (NMR) spectroscopy are used to elucidate the local structure, and they reveal that most of the Li ions are located in transition metal (TM) sites, Preferably surrounded by Mn ions. To characterize structural changes occurring upon electrochemical cycling, in situ synchrotron X-ray diffraction is conducted. It is clearly demonstrated that no significant phase transformation is observed up to 4.4 V charge for this material, unlike Li-free P2-type Na cathodes. The presence of monovalent Li ions in the TM layers allows more Na ions to reside in the prismatic sites, stabilizing the overall charge balance of the compound. Consequently, more Na ions remain in the compound upon charge, the P2 structure is retained in the high voltage region, and the phase transformation is delayed. Ex situ NMR is conducted on samples at different states of charge/discharge to track Li-ion site occupation changes. Surprisingly, Li is found to be mobile, some Li ions migrate from the TM layer to the Na layer at high voltage, and yet this process is highly reversible. Novel design principles for Na cathode materials are proposed on the basis of an atomistic level understanding of the underlying electrochemical processes. These principles enable us to devise an optimized, high capacity, and structurally stable compound as a potential cathode material for high-energy Na-ion batteries.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available