Improving the electrochemical performance of the LiNi0.5Mn1.5O4spinel by polypyrrole coating as a cathode material for the lithium-ion battery

Xuan Wen Gao, Yuan Fu Deng, David Wexler, Guohua Chen, Shu Lei Chou, Hua Kun Liu, Zhi Cong Shi, Jia Zhao Wang

Research output: Journal article publicationJournal articleAcademic researchpeer-review

110 Citations (Scopus)


Conductive polypyrrole (PPy)-coated LiNi0.5Mn1.5O4(LNMO) composites are applied as cathode materials in Li-ion batteries, and their electrochemical properties are explored at both room and elevated temperature. The morphology, phase evolution, and chemical properties of the as-prepared samples are analyzed by means of X-ray powder diffraction, thermogravimetric analysis, Raman spectroscopy, X-ray photoelectron spectroscopy and scanning and transmission electron microscopy techniques. The composite with 5 wt% polypyrrole coating shows a discharge capacity retention of 92% after 300 cycles and better rate capability than the bare LNMO electrode in the potential range of 3.5-4.9 V vs. Li/Li+at room temperature. At the elevated temperature, the cycling performance of the electrode made from LNMO-5 wt% PPy is also remarkably stable (∼91% capacity retention after 100 cycles). It is revealed that the polypyrrole coating can suppress the dissolution of manganese in the electrolyte which occurs during cycling. The charge transfer resistance of the composite electrode is much lower than that of the bare LNMO electrode after cycling, indicating that the polypyrrole coating significantly increases the electrical conductivity of the LNMO electrode. Polypyrrole can also work as an effective protective layer to suppress the electrolyte decomposition arising from undesirable reactions between the cathode electrode and electrolyte on the surface of the active material at elevated temperature, leading to high coulombic efficiency.
Original languageEnglish
Pages (from-to)404-411
Number of pages8
JournalJournal of Materials Chemistry A
Issue number1
Publication statusPublished - 7 Jan 2015
Externally publishedYes

ASJC Scopus subject areas

  • Chemistry(all)
  • Renewable Energy, Sustainability and the Environment
  • Materials Science(all)

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