A commercial LiNi0.5Co0.2Mn0.3O2 (LNCM) cathode material is purposefully modified using a small account of LiPF6 as one precursor via a simple means at low calcination temperature in air. X-ray diffraction, scanning electron microscopy, and transmission electron microscopy images reveal that this modification process keeps the layered bulk structure of LNCM even though the surface components have obviously been modified. Electron energy loss spectroscopy and X-ray photoelectron spectroscopy with different etching depths further prove the formation of LiF and F– doping on the LNCM surface, which simultaneously triggers partial Ni3+ reduction to Ni2+; and the metal–oxygen bond is partially replaced by a higher energy metal–fluorine bond. The modified material (LNCM-2) retains 93.7% of its initial capacity and delivers 179.4 mAh g–1 at a current density of 0.5 C after 100 stable cycles at 3.0–4.5 V. Meanwhile, LNCM-2 is able to maintain capacity retention up to 81.1% after 300 cycles at 5 C, much better than...

Synergistic Effect of F– Doping and LiF Coating on Improving the High-Voltage Cycling Stability and Rate Capacity of LiNi0.5Co0.2Mn0.3O2 Cathode Materials for Lithium-Ion Batteries

Nitrogen-doped carbon-coated Li[Ni0.8Co0.1Mn0.1]O2 cathode material for enhanced lithium-ion storage

Synergistic effects of ion doping and surface-modifying for lithium transition-metal oxide: Synthesis and characterization of La2O3-modified LiNi1/3Co1/3Mn1/3O2

Layered LiNi1/3Co1/3Mn1/3O2 (NCM333) is successfully coated by fast ionic conductor LiTi2(PO4)3 (LTP) via a wet chemical method. The effects of LTP on the physicochemical properties and electrochemical performance are studied. The results reveal that a highly layered structure of NCM333 can be well maintained with less cation mixing after LTP coating. LTP of about 5 nm thickness is coated on the surface of NCM333. Such an LTP coating layer can effectively suppress the side reactions between NCM333 and electrolyte but will not hinder the lithium ion transmission. As a result, LTP-coated NCM333 owns an improved capability and cyclic performance, for example, NCM333/LTP delivers an initial capacity as high as 121.0 mA h g–1 with a capacity retention ratio of 82.3% after 200 cycles at 10 C, whereas NCM333 only has an initial capacity of 120.4 mA h g–1 with a very low capacity retention ratio of 66.4%. This method of using a fast ionic conductor like LTP as a coating material may provide a simple and effective...

Zhaoyang Chen

Papers

Li2O-B2O3-Li2SO4 modified LiNi1/3Co1/3Mn1/3O2 cathode material for enhanced electrochemical performance