Hard templating synthesis of mesoporous and nanowire SnO2 lithium battery anode materials

Mesoporous and nanowire SnO2 anode materials for lithium batteries were prepared using KIT-6 and SBA-15 SiO2 templates, and their electrochemical properties were compared at different current rates. The as-prepared SnO2 nanowires had a diameter of 6 nm and a length of > 3 mum and Brunauer-Emmett-Teller (BET) surface area of 80 m2 g-1 while mesoporous SnO2 showed a pore size of 3.8 nm and a BET surface area of 160 m2 g-1. The charge capacities of these two anodes were similar to each other at 800 mAh g-1, but mesoporous SnO2 showed much improved cycle life performance and rate capabilities because of its higher surface area than nanowire SnO2. Especially, the capacity retention of the mesoporous SnO2 was 98%, compared with 31% for the SnO2 nanowires at a 10 C rate (= 4000 mA g-1). The improved electrochemical performance of the mesoporous SnO2 was related to the regular porosity which permitted thorough flooding of the electrolyte between the particles, and the mesopores which acted as a buffer zone during the volume contraction and expansion of Sn.