Battery performance, such as the rate capability and cycle stability of lithium transition metal oxides, is strongly correlated with the surface properties of active particles. For lithium-rich layered oxides, transition metal segregation in the initial state and migration upon cycling leads to a significant structural rearrangement, which eventually degrades the electrode performance. Here, we show that a fine-tuning of surface chemistry on the particular crystal facet can facilitate ionic diffusion and thus improve the rate capability dramatically, delivering a specific capacity of ∼110 mAh g-1 at 30C. This high rate performance is realized by creating a nanoscale zirconium-abundant rock-salt-like surface phase epitaxially grown on the layered bulk. This surface layer is spontaneously formed on the Li+-diffusive crystallographic facets during the synthesis and is also durable upon electrochemical cycling. As a result, Li-ions can move rapidly through this nanoscale surface layer over hundreds of cycles. This study provides a promising new strategy for designing and preparing a high-performance lithium-rich layered oxide cathode material.
Bibliographical noteFunding Information:
*E-mail: email@example.com. *E-mail: firstname.lastname@example.org. ORCID Juhyeon Ahn: 0000-0002-1701-3372 Jong Hak Kim: 0000-0002-5858-1747 Kyung Yoon Chung: 0000-0002-1273-746X Sangryun Kim: 0000-0001-8617-3022 Jang Wook Choi: 0000-0001-8783-0901 Si Hyoung Oh: 0000-0002-7063-9235 Funding This work was supported by the National Research Foundation of Korea (grant no. NRF-2011-C1AAA001-0030538) and KIST Institutional Program (grant no. 2E27062). Notes The authors declare no competing financial interest.
© 2017 American Chemical Society.
All Science Journal Classification (ASJC) codes
- Materials Science(all)
- Condensed Matter Physics
- Mechanical Engineering