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An abundant hollow nanostructure is crucial for fast Li+ and K+ diffusion paths and sufficient electrolyte penetration, which creates a highly conductive network for ionic and electronic transport. In this study, we successfully developed a molecular-bridge-linked, organic–inorganic hybrid interface that enables the preparation of in situ nitrogen-doped hollow carbon nanospheres. Moreover, the prepared HCNSs, with high nitrogen content of up to 10.4%, feature homogeneous and regular morphologies. The resulting HCNSs exhibit excellent lithium and potassium storage properties when used as electrode materials. Specifically, the HCNS-800 electrode demonstrates a stable reversible discharge capacity of 642 mA h g−1 at 1000 mA g−1 after 500 cycles for LIBs. Similarly, the electrode maintains a discharge capacity of 205 mA h g−1 at 100 mA g−1 after 500 cycles for KIBs. Moreover, when coupled with a high-mass-loading LiFePO4 cathode to design full cells, the HCNS-800‖LiFePO4 cells provide a specific discharge capacity of 139 mA h g−1 at 0.1 C. These results indicate that the HCNS electrode has promising potential for use in high-energy and environmentally sustainable lithium-based and potassium-based batteries. [ABSTRACT FROM AUTHOR]

In a two-phase heat transfer device, achieving a high capillarity of the wick while reducing flow resistance within a limited space becomes the key to improving the heat dissipation performance. As a commonly used wick structure, mesh is widely employed because of its high permeability. However, achieving the desired capillary performance often requires multiple layers to be superimposed to ensure an adequate capillary, resulting in an increased thickness of the wick. In this study, an ultra-thin biomimetic copper forest structural modification of copper mesh was performed using an electrochemical deposition to solve the contradiction between the permeability and the capillary. The experiments were conducted on a copper mesh to investigate the effects of various conditions on their morphology and capillary performance. The results indicate that the capillary performance of the modified copper mesh improves with a longer deposition time. The capillary pressure drops can reach up to 1400 Pa when using ethanol as the working fluid. Furthermore, the modified copper mesh demonstrates a capillary performance value (ΔPc·K) of 8.44 × 10−8 N, which is 1.7 times higher than that of the unmodified samples. Notably, this enhanced performance is achieved with a thickness of only 142 μm. The capillary limit can reach up to 45 W when the modified copper mesh is only 180 μm. Microscopic flow analysis reveals that the copper forest modified structure maintains the original high permeability of the copper mesh while providing a greater capillary force, thereby enhancing the overall flow characteristics. [ABSTRACT FROM AUTHOR]

Graphyne, another two-dimensional carbon allotrope, has received increased attentions in recent years. By using the first-principles density functional calculations combined with the non-equilibrium Green's function formalism, we investigated the electronic, thermal, and thermoelectric transport properties of graphyne systematically and comparatively. It is found that the phonon thermal conductance of graphyne is greatly reduced compared to that of graphene in most temperature regions while larger than that of graphene at low temperatures, which is attributed to the different bond strengths and phonon spectra of graphyne and graphene. Due to the semiconductor property of graphyne, the thermoelectric power (TEP) is found to be one magnitude larger than that of graphene. Besides, distinct peak value regions of TEP in the contour of chemical potential and temperature are displayed for graphyne and graphene. Finally, the thermoelectric figure of merit (ZT) of graphyne is found to be much larger than that of graphene as a result of large TEP and greatly reduced thermal conductance in graphyne, which indicates preferred thermoelectric applications for graphyne. [ABSTRACT FROM AUTHOR]