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Nonpolar a-axial GaN nanowire (NW) was first used to construct the MSM (metal-semiconductor-metal) symmetrical Schottky contact device for application as visible-blind ultraviolet (UV) detector. Without any surface or composition modifications, the fabricated device demonstrated a superior performance through a combination of its high sensitivity (up to 10(4) A W(-1)) and EQE value (up to 10(5)), as well as ultrafast (<26 ms) response speed, which indicates that a balance between the photocurrent gain and the response speed has been achieved. Based on its excellent photoresponse performance, an optical logic AND gate and OR gate have been demonstrated for performing photo-electronic coupled logic devices by further integrating the fabricated GaN NW detectors, which logically convert optical signals to electrical signals in real time. These results indicate the possibility of using a nonpolar a-axial GaN NW not only as a high performance UV detector, but also as a stable optical logic device, both in light-wave communications and for future memory storage.

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The deployment of rechargeable batteries is crucial for the operation of advanced portable electronics and electric vehicles under harsh environment. However, commercial lithium‐ion batteries using ethylene carbonate electrolytes suffer from severe loss in cell energy density at extremely low temperature. Lithium metal batteries (LMBs), which use Li metal as anode rather than graphite, are expected to push the baseline energy density of low‐temperature devices at the cell level. Albeit promising, the kinetic limitations of standard cell chemistries under subzero operation condition inevitably hamper the cyclability of LMBs, resulting in a severe decline in plating/stripping reversibility and short‐circuit hazards due to the dendritic growth. Such performance degradation becomes more pronounced with decreasing temperature, ascribing to sluggish ion transport kinetics during charging/discharging processes which includes Li+ solvation/desolvation, ion transport through bulk electrolyte, as well as ion diffusion within solid electrolyte interphase and bulk electrode materials at low temperature. In this review, the critical limiting factors and challenges for low‐temperature ion transport behaviors are systematically reviewed and discussed. The strategies to enhance Li+ transport kinetics in electrolytes, electrodes, and electrolyte/electrode interface are comprehensively summarized. Finally, perspective on future research direction of low‐temperature LMBs toward practical applications is proposed.