The Effects of Different Core–Shell Structures on the Electrochemical Performances of Si–Ge Nanorod Arrays as Anodes for Micro-Lithium Ion Batteries

Connected and airbag isolated Si–Ge nanorod (NR) arrays in different configurations have been fabricated on wafer scale Si substrates as anodes in micro-lithium ion batteries (LIBs), and the impacts of configurations on electrochemical properties of the electrodes were investigated experimentally and theoretically. It is demonstrated that the Si inner cores can be effectively protected by the connected Ge shells and contribute to the enhanced capacity by ∼68%, derived from an activation process along with the amorphization of the crystalline lattice. The first-principles calculations further verify the smaller forces on the Si layers at the atomic level during the restricted volume expansion with the covering of Ge layers. This work provides general guidelines for designing other composites and core–shell configurations in electrodes of micro-LIBs to accomplish higher capacities and longer cycle lives

High Stability Induced by the TiN/Ti Interlayer in Three-Dimensional Si/Ge Nanorod Arrays as Anode in Micro Lithium Ion Battery

Three-dimensional (3D) Si/Ge-based micro/nano batteries are promising lab-on-chip power supply sources because of the good process compatibility with integrated circuits and Micro/Nano-Electro-Mechanical System technologies. In this work, the effective interlayer of TiN/Ti thin films were introduced to coat around the 3D Si nanorod (NR) arrays before the amorphous Ge layer deposition as anode in micro/nano lithium ion batteries, thus the superior cycling stability was realized by reason for the restriction of Si activation in this unique 3D matchlike Si/TiN/Ti/Ge NR array electrode. Moreover, the volume expansion properties after the repeated lithium-ion insertion/extraction were experimentally investigated to evidence the superior stability of this unique multilayered Si composite electrode. The demonstration of this wafer-scale, cost-effective, and Si-compatible fabrication for anodes in Li-ion micro/nano batteries provides new routes to configurate more efficient 3D energy storage systems for micro/nano smart semiconductor devices

ZIF‑8 Cooperating in TiN/Ti/Si Nanorods as Efficient Anodes in Micro-Lithium-Ion-Batteries

Zeolite imidazolate framework-8 (ZIF-8) nanoparticles embedded in TiN/Ti/Si nanorod (NR) arrays without pyrolysis have shown increased energy storage capacity as anodes for lithium ion batteries (LIBs). A high capacity of 1650 μAh cm^–2 has been achieved in this ZIF-8 composited multilayered electrode, which is ∼100 times higher than the plain electrodes made of only silicon NR. According to the electrochemical impedance spectroscopy (EIS) and ¹H nuclear magnetic resonance (NMR) characterizations, the improved diffusion of lithium ions in ZIF-8 and boosted electron/Li⁺ transfer by the ZIF-8/TiN/Ti multilayer coating are proposed to be responsible for the enhanced energy storage ability. The first-principles calculations further indicate the favorable accessibility of lithium with appropriate size to diffuse in the open pores of ZIF-8. This work broadens the application of ZIF-8 to silicon-based LIBs electrodes without the pyrolysis and provides design guidelines for other metal–organic frameworks/Si composite electrodes