Enhanced electrochemical performance of Li-ion batteries with nanoporous titania as negative electrodes

Nanoporous anatase TiO2 (np-TiO2) electrodes have been developed via the anodization of titanium foils in fluoride containing electrolytes, and its application in rechargeable lithium-ion batteries (LIBs) was investigated. Four different types of np-TiO2 electrodes with different pore diameters of 14.7 +/- 8.2 am, 12.8 +/- 6.8 nm, 11.0 +/- 5.5, and 26.7 +/- 13.6 nm were fabricated for evaluating the effect of nanoporous characteristics on the LIB performance. The discharge capacity of the four battery types 1, 2, 3, and 4 were 132.7 mAh.g(-1), 316.7 mAh.g(-1), 154.3 mAh.g(-1), and 228.4 mAh.g(-1), respectively. In addition, these electrodes 1, 2, 3, and 4 exhibited reversible capacity of 106.9 mAh.g(-1) after 295th, 180.9 mAh.g(-1) after 220th, 126.1 mAh.g(-1) after 150th, and 206.7 mAh.g(-1) after 85th cycle at a rate of 1 C, respectively. It was noted that the cyclic life of the batteries had an inverse relationship, and the capacity had a proportional relationship to the pore diameter. The enhanced electrochemical performance of the nanoporous electrodes can be attributed to the improved conductivity and the enhanced kinetics of lithium insertion/extraction at electrode/electrolyte interfaces because of the large specific surface area of np-TiO2 electrodes.