Core-shell CNT-Ni-Si nanowires as a high performance anode material for lithium ion batteries

Core-shell carbon nanotube (CNT)-Si heterogeneous nanowires have been identified as one of the most promising candidates for future anode materials in lithium ion batteries. However, stress in these nanostructures, is the long-existing bottleneck, rendering severe fading of the capacities and even failure of the batteries. We prove that the interfaces between CNT cores and Si shells play a critical role in the stress engineering. With rationally engineered interfaces, our core-shell nanowires with CNT-Ni-Si structure are able to offer excellent capacity retention and rate performance. Introduction of the rough Ni interfacial layer and utilization of the CNT cores lead to reinforced stability of the structure, well accommodated stress and enhanced charge transfer, which are responsible for the improved performance. This core-shell CNT-Ni-Si nanostructure provides a simple but effective pathway towards realization of long lifetime and high performance lithium ion batteries.