Lithium-Aluminum-Phosphate coating enables stable 4.6 V cycling performance of LiCoO2 at room temperature and beyond

Xiao Wang, Qian Wu, Siyuan Li, Zheming Tong, Duo Wang, Houlong L. Zhuang, Xinyang Wang, Yingying Lu

Research output: Contribution to journalArticlepeer-review

Abstract

Lithium cobalt oxide (LCO), a promising cathode with high compact density around 4.2 g cm−3, delivers only half of its theoretical capacity (137 mAh g−1) due to its low operation voltage at 4.2 V (vs. Li/Li+) under commercial conditions. To improve its practical capacity, higher cut-off voltages are often adopted, which result in severe structure destruction and cause side reactions with electrolyte. The safety concerns of oxygen release further restrict the application of LCO. Here, we achieve stable cycling of LCO at 4.6 V (vs. Li/Li+) through a surface engineering strategy by using lithium-aluminum-phosphate composite coating materials. This strategy prevents direct contact between cathode and electrolyte, reducing the loss of active materials without hindering the lithium ion migration. After calcination, a doping layer (or solid solution) includes phosphorus and aluminum is formed, which helps maintain the surface structure and stabilize the oxygen atoms around particle surface and shows high ion mobility when operated at 4.6 V (vs. Li/Li+). All these benefits synergistically contribute to the stable cycling of LCO at 4.6 V (vs. Li/Li+) with high capacity retentions of 88.6% (30°C) and 78.6% (45°C), respectively, after 200 cycles.

Original languageEnglish (US)
Pages (from-to)67-76
Number of pages10
JournalEnergy Storage Materials
Volume37
DOIs
StatePublished - May 2021

Keywords

  • High-voltage
  • Li-ion batteries
  • LiCoO
  • Phosphorus composites
  • Surface modification

ASJC Scopus subject areas

  • Renewable Energy, Sustainability and the Environment
  • Materials Science(all)
  • Energy Engineering and Power Technology

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