In-situ constructing a rigid and stable dual-layer CEI film improving high-voltage 4.6 V LiCoO2 performances

Yinping Qin, Kaiyun Xu, Qian Wang, Menghan Ge, Tao Cheng, Meng Liu, Hongyu Cheng, Yibo Hu, Cai Shen, Deyu Wang, Yang Liu, Bingkun Guo

Research output: Journal PublicationArticlepeer-review

Abstract

As the most important cathode used in digital devices, LiCoO2 can extract more specific capacity by lifting the operational voltage. But the cyclic performance suffers from rapid decay due to the unstable electrode/electrolyte interphase (CEI) at high voltage. In this work, a novel in-situ dual-layer CEI film with high electrochemical stability and mechanical strength is constructed by sequential oxidation potentials of multiply additives. The inner layer of fluorinated-alkyl amide compounds displays a good oxidative stability to ~4.75 V vs. Li+/Li, and the outer layer of polymerized diphenylamine (DPA) shows an ultrahigh Young's modulus ~ 25.4 GPa. This dual-layer CEI film not only prevents the decomposition of electrolyte and dissolution of Co element, but also mitigates the particles cracking. With the protection of this dual-layer CEI film, the capacity retention of Li/LiCoO2 cells has been improved from ~ 59% to 75% at 4.6 V vs. Li+/Li in 200 cycles. This work provides a new design of constructing stable CEI film for high-energy-density lithium ion batteries (LIBs).

Original languageEnglish
Article number107082
JournalNano Energy
Volume96
DOIs
Publication statusPublished - 1 Jun 2022
Externally publishedYes

Keywords

  • CEI
  • Dual-layer
  • Electrolyte additives
  • High-voltage cathode
  • Mechanical strength

ASJC Scopus subject areas

  • Renewable Energy, Sustainability and the Environment
  • Materials Science (all)
  • Electrical and Electronic Engineering

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