Silicon (Si) and lithium metal are the most favorable anodes for high‐energy‐density lithium‐based batteries. However, large volume expansion and low electrical conductivity restrict commercialization of Si anodes, while dendrite formation prohibits the applications of lithium‐metal anodes. Here, uniform nanoporous Si@carbon (NPSi@C) from commercial alloy and CO2 is fabricated and tested as a stable anode for lithium‐ion batteries (LIBs). The porosity of Si as well as graphitization degree and thickness of the carbon layer can be controlled by adjusting reaction conditions. The rationally designed porosity and carbon layer of NPSi@C can improve electronic conductivity and buffer volume change of Si without destroying the carbon layer or disrupting the solid electrolyte interface layer. The optimized NPSi@C anode shows a stable cyclability with 0.00685% capacity decay per cycle at 5 A g−1 over 2000 cycles for LIBs. The energy storage mechanism is explored by quantitative kinetics analysis and proven to be a capacitance‐battery dual model. Moreover, a novel 2D/3D structure is designed by combining MXene and NPSi@C. As lithiophilic nucleation seeds, NPSi@C can induce uniform Li deposition with buffered volume expansion, which is proven by exploring Li‐metal deposition morphology on Cu foil and MXene@NPSi@C. The practical potential application of NPSi@C and MXene@NPSi@C is evaluated by full cell tests with a Li(Ni0.8Co0.1Mn0.1)O2 cathode.

High-performance cathodes are essential for all kinds of rechargeable batteries, and vanadium pentoxide (V2O5) has wide applications as a cathode in various batteries because of its high theoretical capacity, abundant reserves, and high safety performances. However, the irreversible phase transitions and sluggish ion diffusion limit its advancements. Herein, morphology-tunable micron-sized nanoporous V2O5 arrays are synthesized from V2CT x MXene by a one-step annealing process. The component and structure of the V2CT x MXene are simply controlled by regulating the reaction time. The effects of annealing conditions on crystallinity, microstructure, and electrochemical performance of V2O5 are further probed. The rationally designed V2O5 possesses special porous architecture, 2D structure, and pseudocapacitive effect, which ensures high ion accessibility, excellent structure stability, and fast charge transport. As a consequence, the optimal V2O5 cathode for gel zinc-ion batteries exhibits high capacity (358.7 mA h g–1 at 200 mA g–1 after 400 cycles), superior rate performance (250.4 mA h g–1 at 8000 mA g–1), and stable long-term cyclability (279 mA h g–1 at 2000 mA g–1 over 3500 cycles). The zinc storage enhancing mechanism is assessed by quantitative kinetics analysis. Furthermore, the V2O5 cathode also delivers an improved potassium storage performance. This work may provide a universal avenue to fabricate high-performance electrodes from MXene-based materials for next generation battery systems.

In article number 1908721, Jinkui Feng and co‐workers fabricate uniform nanoporous silicon@carbon (NPSi@C) from commercial alloy and CO2 is fabricated as the anode for lithium ion batteries. The porosity of Si, graphitization degree, and thickness of carbon can be controlled by adjusting the reaction conditions. Moreover, a 2D/3D structure is designed by combining MXene and NPSi@C. As lithiophilic nucleation seeds for the Li metal anode, NPSi@C induces uniform Li deposition with buffered volume expansion.

Thin-film wearable electronics are required to be directly laminated on to human skin for reliable, sensitive bio-sensing but with minimal irritation to the user after long-time use. Excellent heat management films with strongly anisotropic thermal conductivity (K) and adequate breathability are increasingly desirable for shielding the skin from heating while allowing the skin to breathe properly. Here, interfacial self-assembly of a graphene oxide (GO) film covering an ambient-dried bacterial cellulose aerogel (AD-BCA) film followed by laser reduction was proposed to prepare laser-reduced GO (L-rGO)/AD-BCA bilayered films. The AD-BCA substrate provides low cross-plane K (K⊥  ≈  0.052 W mK−1), high breathability, and high compressive and tensile resistance by ‘partially’ inheriting the pore structure from bacterial cellulose (BC) gel. The introduction of an upper L-rGO film, which is only 0.31 wt% content, dramatically increases the in-plane K (K//) from 0.3 W mK−1 in AD-BCA to 10.72 W mK−1 owing to the highly in-plane oriented, continuous, uniform assembling geometry of the GO film; while K⊥ decreases to a lower value of 0.033 W mK−1, mainly owing to the air pockets between L-rGO multilayers caused by the laser reduction. The bilayered films achieve a K///K⊥ of 325, which is substantially larger even than that of graphite and similar polymer composites. They permit high transmission rates for water vapor (416.78 g/m2/day, >204 g/m2/day of normal skin) and O2 (449.35 cm3/m2/day). The combination of strongly anisotropic thermal conductivity and adequate breathability facilitates applications in heat management in on-skin electronics.

Graphene quantum dots (GQDs), as a new class of zero dimensional fluorescent carbon material, have been used in physical, chemical and biological aspects for many interesting properties, such as low toxicity, excellent solubility, high chemical stability, and good surface activity. As a green synthetic method, hydrothermal/solvothermal technology has been applied to effectively control characteristics of GQDs. In this review, we summarize recent work on the hydrothermal/solvothermal synthesis of GQDs and their emerging biological applications.