Effect of Carboxymethyl Cellulose on Aqueous Processing of Natural Graphite Anodes and Their Electrochemical Performance for Lithium Batteries

Published

July 5, 2005

Author(s)

J. H. Lee, U Paik, Vincent A. Hackley, Mark Young

Abstract

Suspensions of natural graphite particles were prepared in an aqueous medium using carboxymethyl cellulose (CMC) and emulsified styrene-butadiene (SB) copolymer latex, as part of an environmentally-friendly fabrication process for graphite anodes intended for application in Li-ion batteries. Suspensions were characterized by adsorption isotherms, electroacoustic measurements, rheology and sedimentation tests, at two different degrees of carboxymethyl substitution (DS) on CMC. A lower DS value (0.7) resulted in greater uptake of CMC on graphite compared with a higher DS value (1.28). This was attributed to attractive hydrophobic interactions associated with the lower carboxymethyl substitution. The greater adsorption for DS = 0.7 correlates with lower relative viscosity in concentrated graphite suspensions, a higher adhesion strength with a copper substrate, and a greater retention of discharge capacity after cycling. The effect of DS is attributed to differences in the aqueous dispersion properties and stability of graphite suspensions. Based on these results, we fabricated high-capacity graphite anodes characterized by gravimetric and volumetric energy densities of greater than 340 mA-h/g and 560 mA-h/cm3, respectively. This formulation also led to improved adhesion strength, giving the as-fabricated cell an attractive cycle life greater than 90% of initial discharge capacity after 200 cycles.

Citation

Journal of the Electrochemical Society

Volume

152

Issue

9

Pub Type

Journals

Keywords

aqueous processing, carboxymethyl cellulose, electrochemical performance, electrokinetic sonic amplitude, graphite, lithium ion battery

Citation

Lee, J. , Paik, U. , Hackley, V. and Young, M. (2005), Effect of Carboxymethyl Cellulose on Aqueous Processing of Natural Graphite Anodes and Their Electrochemical Performance for Lithium Batteries, Journal of the Electrochemical Society (Accessed May 18, 2024)