A chemically activated graphene-encapsulated LiFePO4 composite for high-performance lithium ion batteries

Jeonghyun Ha, Seung Keun Park, Seung Ho Yu, Aihua Jin, Byungchul Jang, Sungyool Bong, In Kim, Yung Eun Sung, Yuanzhe Piao

Research output: Contribution to journalArticlepeer-review

107 Citations (Scopus)

Abstract

A composite of modified graphene and LiFePO4 has been developed to improve the speed of charging-discharging and the cycling stability of lithium ion batteries using LiFePO4 as a cathode material. Chemically activated graphene (CA-graphene) has been successfully synthesized via activation by KOH. The as-prepared CA-graphene was mixed with LiFePO4 to prepare the composite. Microscopic observation and nitrogen sorption analysis have revealed the surface morphologies of CA-graphene and the CA-graphene/LiFePO4 composite. Electrochemical properties have also been investigated after assembling coin cells with the CA-graphene/LiFePO 4 composite as a cathode active material. Interestingly, the CA-graphene/LiFePO4 composite has exhibited better electrochemical properties than the conventional graphene/LiFePO4 composite as well as bare LiFePO4, including exceptional speed of charging-discharging and excellent cycle stability. That is because the CA-graphene in the composite provides abundant porous channels for the diffusion of lithium ions. Moreover, it acts as a conducting network for easy charge transfer and as a divider, preventing the aggregation of LiFePO4 particles. Owing to these properties of CA-graphene, LiFePO4 could demonstrate enhanced and stably long-lasting electrochemical performance.

Original languageEnglish
Pages (from-to)8647-8655
Number of pages9
JournalNanoscale
Volume5
Issue number18
DOIs
Publication statusPublished - 2013 Sep 21
Externally publishedYes

ASJC Scopus subject areas

  • Materials Science(all)

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