摘要
The concentration distributions of binders in dried water-based and organic-based LiCoO 2 electrode sheets are studied, and the effects of binder distributions on the physical, electrical and electrochemical properties of electrodes are also discussed. When the LiCoO 2 slurry is prepared with an organic-based process, the non-uniform distributions of the binder, poly(vinylidene fluoride), and a conductive agent, graphite, are markedly observed in the dried electrode sheet. Nevertheless, these non-uniform distributions of constituents are less significant for the electrode sheet prepared by a water-based process that uses a blend of styrene butadiene rubber and sodium carboxymethyl cellulose as the binder. Beside the experimental results, the binder distributions in the dried electrodes can be accurately predicted via a theoretical calculation based on a migration-controlled drying kinetics. The calculated results show that the organic-based electrode sheet has much higher non-uniformity of binder distribution than the water-based one. Because of the higher non-uniform distributions of binder, the organic-based electrode sheet displays properties of weaker adhesion and higher electrical resistance. Moreover, the electrochemical performance shows that the IR-drop of the organic-based electrode is larger than the water-based one, which has to be reduced by the compression process of electrode sheets. © 2011 The Electrochemical Society.