A High-Rate, High-Capacity, Nanostructured Tin Oxide Electrode

摘要

Recently, Li-ion battery anodes derived from oxides of tin have been of considerable interest because they can, in principle, store more than 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 f capacity and rechargeability. We describe here a nanostructured SnO_2-based electrode that has extraordinary rate capabilities, can deliver very high capacities (e.g., > 700 mAh g~(-1) at the 8C rate), and still retain the ability to be discharged and recharged for as many as 800 cycles. These electrodes, prepared via the template method, consist of monodisperse 110 nm diam SnO_2 nanofibers protruding from a current-collector surface like the bristles of a brush. The dramatically improved rate and cycling performance are 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.