Effectively suppressing dissolution of manganese from spinel lithium manganate via a nanoscale surface-doping approach

The capacity fade of lithium manganate-based cells is associated with the dissolution of Mn from cathode/electrolyte interface due to the disproportionation reaction of Mn( III), and the subsequent deposition of Mn(II) on the anode. Suppressing the dissolution of Mn from the cathode is critical to reducing capacity fade of LiMn2O4-based cells. Here we report a nanoscale surface-doping approach that minimizes Mn dissolution from lithium manganate. This approach exploits advantages of both bulk doping and surface-coating methods by stabilizing surface crystal structure of lithium manganate through cationic doping while maintaining bulk lithium manganate structure, and protecting bulk lithium manganate from electrolyte corrosion while maintaining ion and charge transport channels on the surface through the electrochemically active doping layer. Consequently, the surface-doped lithium manganate demonstrates enhanced electrochemical performance. This study provides encouraging evidence that surface doping could be a promising alternative to improve the cycling performance of lithium-ion batteries.This work was primarily supported by the Center for Electrochemical Energy Science, an Energy Frontier Research Center funded by the US Department of Energy, Office of Science, Office of Basic Energy Sciences, including support for J. L., H. W., J. W. E., K. A. and A. J. K. (X-ray absorption studies). C. Z. and X. Q. were supported by the 973 Programme (2013CB934001, 2009CB220105) of China, Beijing Natural Science Foundation (2120001), National Natural Science Foundation of China (21273129) and 863 programme (2012DGF61480). Y. L. gratefully acknowledges the start-up support by the University of Alabama in Huntsville. Electron microscopy was carried out in the Electron Microscopy Center at Argonne, which is supported by the Office of Science under contract no. DE-AC02-06CH11357. Use of the Advanced Photon Source was supported by the US Department of Energy, Office of Science, Office of Basic Energy Sciences, under contract no. DE-AC02-06CH11357. Y.-K. S. acknowledges the financial support from the Human Resources Development of the Korea Institute of Energy Technology Evaluation and Planning (KETEP) grant funded by the Korea government Ministry of Knowledge Economy (No. 20124010203310) and by the National Research Foundation (NRF) of Korea grant funded by the Korea government (MEST; No. 2009-0092780)