A Li-Rich Layered Oxide Cathode with Negligible Voltage Decay
We acknowledge the financial support by National Key R&D Program of China (2020YFA0406203), the Shenzhen Science and Technology Program (Project No. JCYJ20220818101016034, SGDX2019081623240948), the General Research Fund (GRF) scheme (CityU 11220322), CityU 9610533 and the Shenzhen Research Institute, City University of Hong Kong. We thank X. Zhong and N. Wang for providing consultation on the STEM results. Y.X. and C.M.W. acknowledge support from the Toyota Research Institute through the Accelerated Materials Design and Discovery programme and the National Science Foundation through the MRSEC programme (NSF-DMR 1720139) at the Materials Research Center. We acknowledge the computing resources provided by (1) Quest High-Performance Computing Facility at Northwestern University, which is jointly supported by the Office of the Provost, the Office for Research and Northwestern University Information Technology and (2) Bridges-2 at Pittsburgh Supercomputing Center through allocations dmr160027p and mat220007p from the Advanced Cyber-infrastructure Coordination Ecosystem: Services & Support (ACCESS) programme, which is supported by National Science Foundation grants 2138259, 2138286, 2138307, 2137603 and 2138296. Y.X. was also supported by Portland State University Lab Setup Fund. This research also used resources of the Advanced Photon Source, a US Department of Energy (DOE) Office of Science User Facility operated for the DOE Office of Science by Argonne National Laboratory under contract number DE-AC02-06CH11357.
With high capacity at low cost, Li- and Mn-rich (LMR) layered oxides are a promising class of cathodes for next-generation Li-ion batteries. However, substantial voltage decay during cycling, due to the unstable Li2MnO3 honeycomb structure, is still an obstacle to their practical deployment. Here we report a Co-free LMR Li-ion battery cathode with negligible voltage decay. The material has a composite structure consisting of layered LiTMO2 and various stacked Li2MnO3 components, where transition metal (TM) ions that reside in the Li layers of Li2MnO3 form caps to strengthen the stability of the honeycomb structure. This capped-honeycomb structure is persistent after high-voltage cycling and prevents TM migration and oxygen loss as shown by experimental and computational results. This work demonstrates that the long-standing voltage decay problem in LMRs can be effectively mitigated by internally pinning the honeycomb structure, which opens an avenue to developing next-generation high-energy cathode materials.
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Luo, D., Zhu, H., Xia, Y., Yin, Z., Qin, Y., Li, T., ... & Liu, Q. (2023). A Li-rich layered oxide cathode with negligible voltage decay. Nature Energy, 1-10.