Huixin Chen

Sodium-ion batteries (SIBs) are promising low-cost energy-storage systems, and biomass-derived hard carbon is regarded as an attractive anode material due to its tunable structure and favorable Na+ storage capability. Herein, ramie fiber-derived hard carbons were prepared at different carbonization temperatures to clarify the relationship between microstructure and electrochemical performance. Among them, XW-1400, carbonized at 1400℃, delivered the best overall performance, benefiting from its suitable graphitic ordering, distorted carbon layers, abundant mesopores, and efficient ion-transport pathways. The compatibility of XW-1400 with diglyme-based electrolytes was further investigated. NaPF6/diglyme shows better electrochemical performance. However, the best salt concentration changes with temperature. At room temperature, 1M NaPF6/diglyme works best. But at -20℃, 0.5M NaPF6/diglyme performs better in both cycling stability and rate performance. By using kinetic and interface tests, this result show that the low-concentration electrolyte helps Na+ move faster and lowers charge-transfer resistance. It also helps form a uniform NaF-rich SEI. In comparison, high-concentration electrolytes easily cause ion clustering, salt precipitation, and unstable interfacial reactions at low temperature. These findings show that electrolyte concentration modulation is an effective strategy to improve low-temperature Na+ transport, suppress dendrite growth and interfacial polarization, and enable high-performance SIBs.

Silicon remains the cornerstone in today's immense semiconductor industry. At the nanoscale, silicon could exhibit large elasticity, which holds great potential for flexible electronics and ‘elastic strain engineering’. Here, we report the influence of crystalline orientation, specimen size, strain rate, and electron beam irradiation on the ultra large (>10%) elastic deformation and fracture behavior of VLS‐grown single crystalline silicon nanowires (Si NWs), and demonstrated that Si NWs grown along directions exhibited greater strength and deformability than those along . As the specimen diameters decreased, the fracture strength and strain of Si NWs doubled, and smaller specimens tended to ‘fly away’ upon fracture due to the substantial accumulated elastic potential energy. Results indicate that the intricate mechanical properties of Si NWs are susceptible to multiple intrinsic and extrinsic factors. By strategically manipulating the specific variables, the mechanical robustness and deformation tolerance of Si NW‐based electronic devices can be tailored.

A higher F/C ratio leads to poor conductivity of the fluorinated carbon (CFx) material, resulting in slow kinetics of the lithium-fluorine reaction and thus hindering its application in special fields such as high-power energy storage. By designing and constructing a new type of CFx structure, it is of great significance for improving the rate performance of Li/CFx batteries. Herein, a synergistic strategy of alkaline etching and nitrogen lattice occupation is proposed to construct a CFx material (F‐RG‐US/M) with a gentle gradient defluorination. NaOH achieves gradient defluorination, forming a gentle step-like gradient structure in the material. This structure provides abundant Li+ diffusion pathways while maintaining a reasonable F/C ratio to ensure specific capacity. Urea alters the distribution of electron clouds through nitrogen doping, enhances conductivity, and reduces the C-F bond energy. MWCNTs form an elastic conductive network, which further accelerates the transmission of electrons and ions. Consequently, F‐RG‐US/M exhibits outstanding electrochemical performance, delivering a specific capacity of 765 mA h g-1 with 87.8% capacity retention at a high rate of 20 C. This work not only enables a green, closed‐loop recycling route for spent graphite but also provides a viable pathway for the industrial deployment of high‐power CFx cathodes.

Lithium–sulfur (Li-S) batteries represent a promising candidate for next-generation energy storage systems; however, their practical deployment is impeded by polysulfide shuttle effect and the strong temperature dependence of redox kinetics. Here we develop a wide-temperature Li–S cell enabled by a Ni@JZ-VO2//PP modified separator. The functional interfacial layer consists of a Ni/VO2 heterojunction is uniformly anchored on nitrogen-doped porous carbon derived from distiller’s grains. This architecture effectively regulates polysulfide chemistry from -20 to 60 ℃. The cell delivers 891 mAh g-1 at 4C (50 ℃) and maintains 72.7% capacity after 200 cycles at -20 ℃. At ambient temperature (25 ℃), it provides 766 mAh g-1 at 4C and retains 505 mAh g-1 after 1000 cycles at 1C, corresponding to an exceptionally low average capacity fade rate of 0.054% per cycle. Mechanistically, in-situ XRD and DFT calculations disclose a dual-site catalytic relay: Ni converts in-situ to active NiS2 coupled with Li2S deposition/dissolution, while the NiS2–VO2 interface strengthens Li2S4 binding and alleviates Li2S2 trapping, accelerating polysulfide conversion and suppressing shuttle. This sustainable heterojunction strategy provides a scalable pathway toward high-performance, wide-temperature Li–S batteries.