Temperature induced diameter variation of silicon nanowires via a liquid–solid phase transition in the Zn seed

Herein, we demonstrate the ability of Zn to catalyze the growth of Si nanowires via reaction temperature determined, vapour–liquid–solid (VLS) or vapour–solid–solid (VSS) growth mechanisms. This is the first reported use of a type B catalyst to grow Si nanowires via the VSS mechanism to our knowledge whereby the highly faceted Zn seeds resulted in an increased NW diameter. This was used to induce diameter variations along the axial length of individual nanowires by transitioning between VLS and VSS growth

Lithiophilic nanowire guided Li deposition in Li metal batteries

Lithium (Li) metal batteries (LMBs) provide superior energy densities far  beyond current Li-ion batteries (LIBs) but practical applications are hindered  by uncontrolled dendrite formation and the build-up of dead Li in “hostless”  Li metal anodes. To circumvent these issues, we created a 3D framework of  a carbon paper (CP) substrate decorated with lithiophilic nanowires (silicon  (Si), germanium (Ge), and SiGe alloy NWs) that provides a robust host for  efficient stripping/plating of Li metal. The lithiophilic Li22Si5, Li22(Si0.5Ge0.5)5, and Li22Ge5 formed during rapid Li melt infiltration prevented the forma?tion of dead Li and dendrites. Li22Ge5/Li covered CP hosts delivered the best  performance, with the lowest overpotentials of 40 mV (three times lower  than pristine Li) when cycled at 1 mA cm−2 /1 mAh cm−2  for 1000 h and at  3 mA cm−2 /3 mAh cm−2  for 500 h. Ex situ analysis confirmed the ability of  the lithiophilic Li22Ge5 decorated samples to facilitate uniform Li deposi?tion. When paired with sulfur, LiFePO4, and NMC811 cathodes, the CP-LiGe/ Li anodes delivered 200 cycles with 82%, 93%, and 90% capacity retention,  respectively. The discovery of the highly stable, lithiophilic NW decorated CP  hosts is a promising route toward stable cycling LMBs and provides a new  design motif for hosted Li metal anodes. </p