In situ synthesis of CuxO/SnOx@CNT and CuxO/SnOx@SnO₂/CNT nanocomposite anodes for lithium ion batteries by a simple chemical treatment process.

SnO2-based electrodes for lithium ion batteries (LIBs) typically exhibit high initial specific capacity but poor cycling performance. A possible strategy to improve the cycling performance is to prepare nanocomposites containing SnO2. Here we demonstrate a straightforward method to prepare composites containing SnOx and CuxO by a simple chemical treatment of the LIB electrode on copper foil. The in situ formation of a multiphase composite results in a dramatic improvement in the cycling performance, so that specific capacities exceeding 580 and 800 mA·h/g can be obtained after 70 charge/discharge cycles for CuxO/SnOx@CNT and CuxO/SnOx@SnO2/CNT electrodes, respectively (compared to <100 mA·h/g for pure SnO2). The capacity retention achieved at the 70th cycle compared to the 2nd cycle was 96% for the CuxO/SnOx@CNT electrode. The mechanisms responsible for the formation of a composite material and the improvement in the performance are discussed.