Impact of binder choice on the performance of alpha-Fe2O3 as a negative electrode

The electrochemical performance of negative electrodes based on commercially available micrometer-sized alpha-Fe2O3 powder and four different binders was investigated. alpha-Fe2O3 electrodes made using sodium carboxymethyl cellulose binder and two proprietary binders show better cycling performance than electrodes made from the conventional binder, polyvinylidene fluoride (PVDF). Heat-treating the PVDF electrodes to 300 degrees C improves electrode performance dramatically. A specific capacity of over 800 mAh/g for over 100 cycles has been achieved for Li/alpha-Fe2O3 cells with micrometer-sized alpha-Fe2O3, by contrast to many teachings in the literature where it is claimed nanometer sized particles are required to obtain such performance. As is the case for composite electrodes made from powders of metal alloys, we suggest that binder choice has a great impact on the performance of metal oxide electrodes demonstrating large volume expansion during lithiation, such as alpha-Fe2O3. (c) 2008 The Electrochemical Society.