Nanomaterial-based Li-ion battery electrodes

We have been exploring the use of the template method to prepare nanostructured Li-ion battery electrodes. These nanostructured electrodes show improved rate capabilities relative to thin-film control electrodes prepared from the same material. In this paper we discuss nanostructured Sn-based anodes. Li-ion battery anodes derived from oxides of tin have been of considerable recent interest because they can, in principle, store over twice as much Li+ as graphite. However, large volume changes occur when Li+ is inserted and removed from these Sn-based materials, and this causes internal damage to the electrode resulting in loss of capacity and rechargability. We describe here a new nanostructured SnO2-based electrode that has extraordinary rate capabilities, can deliver very high capacities (e.g. >700 mAh g−1 at 8°C), and still retain the ability to be discharged and recharged through as many as 800 cycles. These electrodes, prepared via the template method, consist of monodisperse 110 nm-diameter SnO2 nanofibers protruding from a current-collector surface like the bristles of a brush. The dramatically-improved rate and cycling performance is related to the small size of the nanofibers that make up the electrode and the small domain size of the Sn grains within the nanofibers.