Improvement of electrochemical performance of LiMn2O4 composite cathode by ox-MWCNT addition for Li-ion battery

• Autor(a) principal: Liu,Su-qin
• Data de Publicação: 2008
• Outros Autores: Zhang,Jian-feng, Huang,Ke-long, Yu,Jin-gang
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Journal of the Brazilian Chemical Society (Online)
• Texto Completo: http://old.scielo.br/scielo.php?script=sci_arttext&pid=S0103-50532008000600005
• topic: oxidized multi-walled carbon nanotubes; composite electrode; conducting network; lithium ion batteries

Oxidized multi-walled carbon nanotubes (ox-MWCNT) were used as conducting addition to prepare a novel network composite cathode for lithium ion battery. The morphology was analyzed by scanning electron microscope, LiMn2O4 active particles were connected by ox-MWCNT with the formation of three-dimensional networking wiring. Electron transport and electrochemical activity were improved effectively. Galvanostatic charge-discharge tests of LiMn2O4/ox-MWCNT cathode showed that the initial discharge capacities are 119.4, 110.6, 105.5 and 91.4 mAh g-1 at the rate of 0.1, 0.5, 1 and 2 C, respectively, which were much higher than LiMn2O4/acetylene black (AB) at the same content. The electrochemical AC impedance spectroscopy showed that the charge transfer resistance (Rct) of the composite electrode reduced obviously contrasting to 34.32 Ω for LiMn2O4/ox-MWCNT and 53.2 Ω for LiMn2O4/AB. Overall, it is found that a conductive network to facilitate electron transfer and good connection of the active-material particle to the network were playing an important role to rate capability and cycle efficiency.