Fabrication and Electrochemical Performance of Interconnected Silicon Nanowires Synthesized from AlCu Catalyst

Highly interconnected silicon nanowires (SiNW) were prepared by a vapor−liquid−solid process using a multilayered AlCu film as the catalyst. The resulting SiNWs had a branched and interconnected structure where the AlCu catalyst was incorporated into the SiNWs. The electrochemical lithiation of the SiNWs was investigated through both deep and shallow cycling. The first cycle Coulombic efficiency for lithiation/delithiation was 93.6% which increased to 99.96% upon cycling. The interconnected nanowire structures assisted in retaining a high Coulombic efficiency upon cycling by limiting the loss of active material during nanowire fracture and providing shorter/multiple electrical paths to the substrate. The performance for repeated shallow discharges, as encountered in a microbattery configuration for wireless sensors, was evaluated.