solutions, explorative studies of the electro-redox couples, with the concurrent high retrievable capacity, enlarged nominal voltage gap, and rapid reaction kinetics, hold the key to promote the energy-dense battery construction at the extreme power output. [1] For the lithium ion batteries, the energy densities of traditional formats (LiCoO 2 /LiFePO 4 cathodes and graphite anodes) have approached their theoretical limits. [2] Alternatively, the unit cell prototyping of the high-capacity Li metal anode with the nickel-rich cathode can achieve the enhanced level of energy densities at the device level. [3,4] When soaking this electrode couples in the conventional carbonate-based electrolytes, however, the Fermi-energy incompatibility at the multiscale interface would cause the uncontrollable dendrite growth on the metallic foil and cathode structure collapse upon the high-voltage cycling. [5] Therefore, the reliable operation of the energy-dense battery necessitates the harmony balance of the enlarged voltage gap and the interfacial stability at multiple scales, yet still remains challenging.As the most attractive cathode type of the practical relevance, nickel-rich (Ni content >0.8) layered oxides exhibit the merits of the large specific capacity (>200 mAh g −1 ), environmental benignity and relative lower cost as compared to the LiCoO 2 cathode. Despite of the dominant nickel occupancy in the layered oxides for elevating the Li storage sites, the increased nickel ratio adversely deteriorates the cycle performance. The transition metal (TM) layer of the oxide structure at the highvoltage charged states would oxidize the carbonate solvents in the presence of moisture, leading to serious self-discharge rates upon the high-temperature storage. [6] Additionally, the hydrofluoric acid (HF) formed by the decomposition of the lithium hexafluorophosphate (LiPF 6 ) salt aggravates the TM ions (Co 2+ , Ni 2+ , and Mn 2+ ) dissolution and structural collapse of the layered cathode, meanwhile the TM species would deposit on the anode surface and degrade the solid electrolyte interface (SEI). [7] So far, a plethora of mitigation strategies were implemented to insulate the direct contact of the oxide particles with the electrolyte, for instance the exquisite coatings with The reliable operation of Li metal batteries suffers from cathode collapse due to high-voltage cycling, interfacial reactivity of the Li deposits, self-discharge at the elevated temperatures, as well as the power output deterioration in low-temperature scenarios. In contrast to the individual electrode optimization, herein, a hetero-layered separator with an asymmetric functional coating on polyethylene is proposed in response to the aforementioned issues: On the face-to-cathode side, the hybrid layer of the molecular sieve and sulfonated melamine formaldehyde can scavenge the hydrofluoric acid and moisture residues from the carbonate electrolyte, maintaining the cathode robustness in both the high-voltage cycling or high-temperature storage scenarios; while...

The emerging soft robots have attracted increasing interests and gotten rapidly developed, but it is still challenging to substantially promote their response speed and work density. In addition, the wireless way to conveniently trigger the devices, especially for the centimeter‐scale ones, is highly desired. Herein, the multistimuli‐responsive insect‐scale soft robotics is reported based on a super‐aligned VO2 nanowire arrays (NAs)/carbon nanotube (CNT) bimorph film, comprehensively addressing aforementioned problems. The as‐prepared VO2 NA/CNT bimorph shows improved actuation performance, anisotropic behavior, rapid response to various stimuli (heat, light, and electricity), and multiple movement modes (bending and torsion). Consequently, diverse untethered, insect‐scale soft robots, serving as biomimetic crawler, lifter, gripper, wing of flying robots, torsional robot, and so on are successfully demonstrated. The findings provide an effective strategy to develop high‐performance macroscopic mechanical devices by assembling functional nanostructures.

Single-crystalline vanadium dioxide nanowires (VO2 NWs) have attracted significant interest due to their unique characteristics, which originate from the single-domain metal–insulator phase transition (MIT) property. However, the lack of facile technologies to produce vertical nanowire arrays (NAs) in a large area has limited the mass fabrication of VO2-based devices. Here, an antimony-assisted hydrothermal method is developed for the low-temperature production of wafer-scale vertical VO2 NAs on arbitrary substrates of glass, quartz, and silicon. Sb2O3 plays a key role in the controlled growth of pure VO2 (M1) by modulating the size, density, alignment, and MIT properties of VO2 NAs. Furthermore, the growth mechanism of vertical VO2 NAs is explained. In contrast to conventional fabrication technologies, the weak interaction between NA films and substrates enables a much easier transfer of VO2 NAs for various potential applications.

Stress/strain engineering is believed to be an effective way to adjust the thermal conductivity of materials dynamically or as needed. Compared with bulk materials, micro‐/nanoscale structures can withstand greater stress/deformations that lead to evident changes in their thermal conductivity after undergoing stress/strain; this phenomenon has been predicted by theoretical simulations. Nevertheless, measuring the effective thermal conductivity of a single wire of a small size upon controllable bending angles has faced major challenges. Herein, a method using VO2 tag as a temperature indicator is developed to achieve the in situ quantitative measurement of the thermal conductivity of bent silicon microwires (MWs), where thermally insulated spider silk is used to adjust the position of the suspended end of wires for different bending angles. It is found that the thermal conductivity of Si wires increases and then decreases upon subsequent bending; it indicates that the thermal conductivity of MWs can be dynamically tuned by bending. Further studies reveal that the variation of thermal conductivity is reversible with small bending (elastic) and irreversible with large bending (plastic). With this setup, new thermophysical properties of materials are explored at small scales, and possible stress/strain‐gated thermal switches emerge.

Chemical vapor deposition (CVD) has been widely used to produce high quality 2D transitional metal dichalcogenides (2D TMDCs). However, violent evaporation and large diffusivity discrepancy of metal and chalcogen precursors at elevated temperatures often result in poor regulation on X:M molar ratio (M = Mo, W etc.; X = S, Se, and Te), and thus it is rather challenging to achieve the desired products of 2D TMDCs. Here, a modified spatially confined strategy (MSCS) is utilized to suppress the rising S vapor concentration between two aspectant substrates, upon which the lateral/vertical growth of 2D WS 2 can be selectively regulated via proper S:W zones correspond to greatly broadened time/growth windows. An S:W‐time (SW‐T) growth diagram was thus proposed as a mapping guide for the general understanding of CVD growth of 2D WS 2 and the design of growth routes for the desired 2D WS 2 . Consequently, a comprehensive growth management of atomically thin WS 2 is achieved, including the versatile controls of domain size, layer number, and lateral/vertical heterostructures (MoS 2 ‐WS 2 ). The lateral heterostructures show an enhanced hydrogen evolution reaction performance. This study advances the substantial understanding to the growth kinetics and provides an effective MSCS protocol for growth design and management of 2D TMDCs.