Nanoscale Manipulation of Spinel Lithium Nickel Manganese Oxide Surface by Multisite Ti Occupation as High-Performance Cathode.
basic_science · Level V
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- Record sourced from PubMed, PMID 29076229.
- Also identified by DOI 10.1002/adma.201703764.
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Abstract
A novel two-step surface modification method that includes atomic layer deposition (ALD) of TiO<sub>2</sub> followed by post-annealing treatment on spinel LiNi<sub>0.5</sub> Mn<sub>1.5</sub> O<sub>4</sub> (LNMO) cathode material is developed to optimize the performance. The performance improvement can be attributed to the formation of a TiMn<sub>2</sub> O<sub>4</sub> (TMO)-like spinel phase resulting from the reaction of TiO<sub>2</sub> with the surface LNMO. The Ti incorporation into the tetrahedral sites helps to combat the impedance growth that stems from continuous irreversible structural transition. The TMO-like spinel phase also alleviates the electrolyte decomposition during electrochemical cycling. 25 ALD cycles of TiO<sub>2</sub> growth are found to be the optimized parameter toward capacity, Coulombic efficiency, stability, and rate capability enhancement. A detailed understanding of this surface modification mechanism has been demonstrated. This work provides a new insight into the atomic-scale surface structural modification using ALD and post-treatment, which is of great importance for the future design of cathode materials.