A Collaboration of Surface Protection and Bulk Doping for High‐performance Li‐rich Cathode Materials
Author(s) -
Wang MinJun,
Yu FuDa,
Sun Gang,
Gu DaMing,
Wang ZhenBo
Publication year - 2019
Publication title -
chemistryselect
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.437
H-Index - 34
ISSN - 2365-6549
DOI - 10.1002/slct.201901101
Subject(s) - materials science , cathode , faraday efficiency , doping , scanning electron microscope , electrochemistry , scanning transmission electron microscopy , transmission electron microscopy , chemical engineering , electrode , nanotechnology , drop (telecommunication) , analytical chemistry (journal) , composite material , optoelectronics , chemistry , electrical engineering , chromatography , engineering
Abstract Li‐rich layered oxides (LLRO) are promising high energy‐density cathode, but always suffer from the oxygen loss in initial activation and gradual structure transformation during cycling, which leads to capacity degradation and potential decay. Here, we employ a simple strategy to achieve the collaboration of surface protection and bulk doping for improving the performance of Li‐rich material. Scanning electron microscope and transmission electron microscopy tests demonstrate that a nanoscale protective layer of magnesium pyrophosphate is uniformly coated on the Li‐rich material surface. X‐ray diffraction test indicates Mg 2+ and P 2 O 7 4− are incorporated into the crystal structure, which induces the larger lattice spacing and lower cation mixing. As a result, the resultant LLRO displays extremely high Coulombic efficiency of 91.8% and discharge capacity of 288.4 mAh g −1 , showing prominent cycling stability of 89.2% after 200 cycles. Furthermore, our strategy also suppresses the attenuation of average voltage during cycling and the potential drop is only 0.56 mV per cycle from 25 th to 200 th cycle. The excellent electrochemical performance can be ascribed to the combined merits of surface protection and bulk doping. This strategy may provide some new insights into the design and synthesis of high‐performance electrode materials.