Affiliation:
1. Chemical Sciences Division Oak Ridge National Laboratory Oak Ridge TN 37831 USA
2. Center for Nanophase Materials Sciences Oak Ridge TN 37831 USA
3. Department of Chemistry Institute for Advanced Materials and Manufacturing University of Tennessee Knoxville TN 37996 USA
Abstract
AbstractHigh‐capacity cathodes (LiNi0.8Mn0.1Co0.1O2, NMC811) are promising for vehicle electrification because of their high gravimetric energy density. However, their electrochemical performance still relies upon the stability of the cathode electrolyte interphase (CEI). A highly reactive cathode interface leads to parasitic side reactions with electrolytes, resulting in accelerated capacity fading. Well‐developed LiF and LiF‐like inorganic compounds are believed to be good CEI components for stabilizing such reactive electrode interfaces. However, it is challenging to form an optimal surface sub‐nanolayer of LiF on the cathode surfaces because of the complexity of the electrochemical reaction during battery cycling. Herein, the formation of a conformal LiF layer on the NMC811 electrode surface via an in situ ion‐exchange metathesis process is reported, demonstrating a promising electrochemical performance because of a LiF‐stabilized CEI. In situ generated LiF‐coated NMC811 electrodes exhibit ≈97% capacity retention up to 100 cycles at a 0.3 C rate with average coulombic efficiency of ≈99.9% and ≈80% capacity retention up to 200 cycles at a 1 C rate with average coulombic efficiency of >99.6%. This finding may pave the way for reengineering the CEI to enhance the electrochemical performances and cycling stability of the high‐capacity cathodes.
Funder
U.S. Department of Energy
Office of Science
Basic Energy Sciences
Subject
Electrochemistry,Condensed Matter Physics,Biomaterials,Electronic, Optical and Magnetic Materials