Electrochemical Performance of a Water-Based LiFePO<sub>4</sub> Cathode for Li-Ion Batteries

Lithium iron phosphate (LiFePO 4 ) batteries have received much attention because they can provide higher power density with abundant raw materials, better safety, low toxicity, and high thermal stability. In general, the production of LiFePO 4 cathodes uses polyvinylidene fluoride (PVDF) as a binder and N-methyl-2-pyrrolidone (NMP) as a solvent. These components are expensive, toxic, and can adversely affect the environment. Therefore, to address these shortcomings, the solvent and binder were replaced in this study. The solvent in the current study is water. The water soluble binders employed in this study are carboxymethyl cellulose (CMC) and styrene-butadiene rubber (SBR). Suitable electrode formulations were investigated to obtain high performance cylindrical Li-ion batteries. As a result, a formulation with a ratio of LiFePO 4 :AB:KS6:SBR:CMC equal to 90:3:3:2.677:1.333 was used. It has a high specific discharge capacity, 120 mAh/g. This NMP-based cathode can yield about 145 mAh/g, which is slightly higher than a water-based LiFePO 4 cathode.