Pechini process-derived tin oxide and tin oxide-graphite composites for lithium-ion batteries

The Pechini process [Ceram. Bull. 68 (1989) 1002] is used to obtain fine tin oxide powders that reduce the specific volume change in Li- insertion and extraction reactions. The suitability of these tin oxides as active materials for negative electrodes in lithium-ion batteries is investigated. From elemental analysis, it is found that the templating polymer network is almost completely obliterated after heating at 500 degreesC. The best tin oxide does not exhibit extensive crystallization of tin atoms even after 30 cycles of alloying and de-alloying reactions with Li. The structure and the specific capacity of the oxides are dependent on the heat treatment and remnants of the polymeric C-H network can impose an unfavorable outcome. A capacity of 600 mAh g(-1), which is unchanged for 30 cycles, can be obtained from tin oxide heat treated at 1000 degreesC. Composites of graphite and SnO2 are also prepared and exhibit synergistic interactions between graphite and tin oxide which are similar to those reported previously [Electrochem. Solid State Lett. 3 (2000) 167]. (C) 2002 Elsevier Science B.V. All rights reserved.