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Nano‐Sized AlPO 4 Coating Layer on Graphite Powder to Improve the Electrochemical Properties of High‐Voltage Graphite/LiNi 0.5 Mn 1.5 O 4 Li‐Ion Cells
Author(s) -
Zeng Huanna,
He Jia,
Fang Danyang,
Liang Yaohui,
Zhao Ruirui,
Cai Yuepeng,
Lu Dongsheng
Publication year - 2019
Publication title -
energy technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.91
H-Index - 44
eISSN - 2194-4296
pISSN - 2194-4288
DOI - 10.1002/ente.201801078
Subject(s) - graphite , materials science , faraday efficiency , electrolyte , anode , chemical engineering , cathode , electrochemistry , coating , dissolution , carbon fibers , electrode , nanotechnology , composite material , chemistry , composite number , engineering
A high‐voltage graphite/LiNi 0.5 Mn 1.5 O 4 (LNMO) system is a promising candidate for next‐generation Li‐ion batteries with a high energy density. However, it has the drawback of severe capacity fading caused by the consumption of active Li + ions due to the reduction of the products of electrolyte oxidation and LNMO dissolution from the LNMO cathode on the graphite anode. Herein, graphite coated with different amounts of AlPO 4 (0.5, 1, and 2.5 wt%) is prepared by an electrostatic attraction combined with a precipitation conversion method, and used as an anode for the LNMO/graphite full cell. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), and elemental mapping images show that AlPO 4 disperses homogeneously on the surface of graphite, and its thickness is between 10 and 30 nm. Electrochemical measurement results show that LNMO/AlPO 4 @graphite cells show better cycling stability and higher coulombic efficiency than the LNMO/graphite cell. Among them, the LNMO/0.5 wt% AlPO 4 @graphite cell shows the best cycling stability. By combining all the analytical results, the improvement mechanism of LNMO/AlPO 4 @graphite cells is mainly that the side reactions that consume the active Li + ions are greatly reduced because the AlPO 4 coating can block the migration of the products of electrolyte oxidation and LNMO dissolution to the graphite.