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The superior electrochemical performance of a Li-rich layered cathode material with Li-rich spinel Li4Mn5O12 and MgF2 double surface modifications.
- Source :
- Journal of Materials Chemistry A; 4/28/2020, Vol. 8 Issue 16, p7991-8001, 11p
- Publication Year :
- 2020
-
Abstract
- Although Li-rich layered materials are some of the best potential cathode materials owing to their high capacity (>250 mA h g<superscript>−1</superscript>), low cost and reduced pollution, they still faces some problems, including low initial coulombic efficiency, poor cycling performance, and bad rate capability. In this work, Li-rich spinel Li<subscript>4</subscript>Mn<subscript>5</subscript>O<subscript>12</subscript> and MgF<subscript>2</subscript> are constructed on the surface of a Li-rich layered material by simple liquid-phase erosion and liquid-phase deposition methods, respectively. The Li-rich spinel Li<subscript>4</subscript>Mn<subscript>5</subscript>O<subscript>12</subscript> layer provides 3D Li-ion channels and it restrains the growth of SEI film and oxygen release. The outermost amorphous MgF<subscript>2</subscript> layer of coating also favors Li-ion migration and further protects Li<subscript>4</subscript>Mn<subscript>5</subscript>O<subscript>12</subscript> from HF corrosion. It is found that the double surface modifications induce a phase transformation from a layered structure to an Li<subscript>4</subscript>Mn<subscript>5</subscript>O<subscript>12</subscript>-type spinel during cycling, which is different from the traditional structural transformation from a layered structure to a LiMn<subscript>2</subscript>O<subscript>4</subscript> spinel-like structure, and it exhibits a slower structural transformation. Benefiting from these collaborative contributions from Li<subscript>4</subscript>Mn<subscript>5</subscript>O<subscript>12</subscript> and MgF<subscript>2</subscript>, the material shows superior electrochemical properties, including a high initial coulombic efficiency of 96.4%, excellent capacity retention of 80% after 300 cycles, a small voltage decay rate of 1.5 mV per cycle, and a remarkable rate capability. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 20507488
- Volume :
- 8
- Issue :
- 16
- Database :
- Complementary Index
- Journal :
- Journal of Materials Chemistry A
- Publication Type :
- Academic Journal
- Accession number :
- 142948179
- Full Text :
- https://doi.org/10.1039/d0ta00355g