This study investigates the effectiveness of catalytic decomposition of methane for producing turquoise hydrogen and solid carbon nanomaterials. The focus is on developing cost-effective and high-performance Nickel (Ni)-promoted perovskite oxide catalysts. A series of transition metal, Ni-promoted (La_0.75Ca_0.25)(Cr_0.5Mn_0.5)O_3-δ (LCCM) catalysts have been successfully prepared using water-based gel-casting technology. These catalysts are designed to decompose methane into turquoise hydrogen and carbon nanomaterials, achieving negligible CO₂ emissions. X-ray diffraction results indicate that the solubility of Ni at the B-site of LCCM perovskite is limited, x ≤ 0.2. Field Emission Scanning Electron Microscopy analysis of xNi-LCCM, calcined at 1050 °C for ten h in the air, confirms severe catalyst sintering with excess nickel oxide distributed around the LCCM particles. At a 750 °C operating temperature, a Ni to LCCM molar ratio of 1.5 yields a maximum carbon output of 17.04 g_C/g_Ni. Increasing the molar ratios to 2.0 and 2.5 results in carbon yields of 17.17 g_C/g_Ni and 17.63 g_C/g_Ni, respectively, showing minor changes. The morphology of the carbon nanomaterials is unaffected by the molar ratio of NiO promoter to LCCM and remains nearly the same within the scope of this study.

Carbon-based supercapacitors have emerged as promising energy storage components for renewable energy applications due to the unique combination of various physicochemical characteristics in porous carbon materials (PCMs) that can improve specific capacitance (SC) properties. It is essential to develop a methodical approach that exploits the synergy of these effects in PCMs to achieve superior capacitance performance. In this study, machine learning (ML) provided a clear direction for experiments in the screening of key physicochemical features; SHapley Additive exPlanations analysis on ML indicated that specific surface area and specific doping species had a significant synergistic impact on SC enhancement. Utilizing these insights, an O, N co-doped hierarchical porous carbon (ONPC-900) was synthesized using a synergistic pyrolysis strategy through K₂CO₃-assisted in-situ thermal exfoliation and nanopore generation. This method leverages the role of carbon nitride (graphite-phase carbon nitride) as an in-situ layer-stacked template and the oxygen (O)-rich properties of the pre-treated lignite, enabling controlled synthesis of graphene-like folded and amorphous hybrid structures engineered for the efficient N and O doping sites and high specific surface area, resulting in an electrode material with enhanced structural adaptability, rapid charge transfer, and diffusion mass transfer capacity. Density functional theory (DFT) calculations further confirmed that pyrrole nitrogen (N-5), carboxyl (-COOH) active sites, and the defect structure formed by pores synergically enhanced the adsorption of electrolyte ions (K⁺) and electron transfer, improving the SC performance. The optimized ONPC-900 electrode exhibited impressive SC properties of 440 F g^-1 (0.5 A g^-1), outperforming most coal-based PCMs. This study provides a methodology for designing and synthesizing high SC electrode materials by optimizing the key characteristic parameters of synergism from complex structure-activity relationships through the combination of ML screening, experimental synthesis, and density functional theory validation.

Zinc-ion batteries (ZIBs) are being explored as a potential alternative to lithium-ion batteries owing to the growing demand for safer, more sustainable, cost-effective energy storage technologies. In such systems, electrolytes, as one of the key components, have a decisive impact on their electrochemical performance. However, Zn anodes in traditional aqueous electrolytes exhibit drawbacks such as severe hydrogen evolution reactions, Zn corrosion and passivation especially at high temperatures, leading to poor cycling performance of ZIBs. Herein, we designed and evaluated a series of hybrid electrolytes consisting of zinc tetrafluoroborate hydrate [Zn(BF₄)₂·xH₂O] as the solute and various organic solvents [tetraglyme (G4), propylene carbonate, and dimethylformamide] for high-temperature ZIBs. Comparative analysis revealed that G4-based hybrid electrolytes exhibit a unique Zn²⁺ solvation structure primarily surrounded by organic solvent rather than H₂O, which substantially reduces H₂O-related side reactions and thus promotes more reversible Zn deposition than propylene carbonate-based and dimethylformamide-based hybrid electrolytes. The superiority of G4-based hybrid electrolyte is further confirmed by long stable cycling life of the corresponding Zn||Zn symmetric cell (> 350 h) and Zn-ion capacitor full cell (over 1,400 cycles with 90.7% capacity retention) at 60 °C.

The lattice oxygen mechanism (LOM) plays a critical role in the acidic oxygen evolution reaction (OER) as it provides a more efficient catalytic pathway compared to the conventional adsorption evolution mechanism (AEM). LOM effectively lowers the energy threshold of the reaction and accelerates the reaction rate by exciting the oxygen atoms in the catalyst lattice to directly participate in the OER process. In recent years, with the increase of in-depth understanding of LOM, researchers have developed a variety of iridium (Ir) and ruthenium (Ru)-based catalysts, as well as non-precious metal oxide catalysts, and optimized their performance in acidic OER through different strategies. However, LOM still faces many challenges in practical applications, including the long-term stability of the catalysts, the precise modulation of the active sites, and the application efficiency in real electrolysis systems. Here, we review the application of LOM in acidic OER, analyze its difference with the traditional AEM mechanism and the new oxide pathway mechanism (OPM) mechanism, discuss the experimental and theoretical validation methods of the LOM pathway, and prospect the future development of LOM in electrocatalyst design and energy conversion, aiming to provide fresh perspectives and strategies for solving the current challenges.

With the extremely high theoretical energy densities, secondary batteries including lithium-sulfur (Li-S) and sodium-sulfur (Na-S) batteries are anticipated to become the leading candidates among metal-sulfur batteries. However, the practical energy density and storage efficiency of Li/Na-sulfur batteries are significantly hindered by several issues: the low conductivity of sulfur cathodes, substantial volume changes during charge and discharge cycles, the shuttle effect caused by metal polysulfides, and uncontrollable dendrite formation on the reactive alkali metal anodes, which also heighten safety concerns. Constructing functionalized separators is considered one of the most promising strategies to overcome these challenges and enhance the performance of Li/Na-sulfur batteries. Functionalized separators offer numerous advantages such as enhanced mechanical stability, bifunctionality in suppressing the shuttle effect and dendrite growth, and minimal impact on battery energy density and volume. However, comprehensive reviews of Li/Na-sulfur functionalized separators are relatively fewer, while the related research has increased significantly. In this context, it is crucial to provide a comprehensive review of recent advances in functionalized separators for Li/Na-sulfur batteries. First, this review offers an in-depth analysis of the current issues faced by Li/Na-sulfur batteries and summarizes the requirements of separators for improving Li/Na-sulfur batteries. Subsequently, a detailed discussion is presented about the performances and applications especially in shuttle effect inhibition and dendrite growth suppression of functionalized separators in Li-S and Na-S batteries. Finally, the review addresses the challenges and potential future research directions for functionalized separators in Li/Na-sulfur batteries.

Lithium metal batteries are considered highly promising candidates for the next-generation high-energy storage system. However, the growth of lithium dendrites significantly hinders their advance, particularly under high current densities, due to the formation of unstable solid electrolyte interphase (SEI) layers. In this study, we demonstrate that molybdenum-based MXenes, including Mo₂CT_x, Mo₂TiC₂T_x, and Mo₂Ti₂C₃T_x, form more stable LiF/Li₂CO₃ SEI layers during lithium plating, compared to the conventional Cu electrode. Among these, the bimetallic Mo₂Ti₂C₃T_x MXene, with its higher fluorine terminations, produces the most stable LiF-rich SEI layer. The formation of this stable inorganic SEI layer significantly reduces the nucleation overpotential for lithium deposition, promotes uniform Li deposition, and suppresses dendrite growth. Consequently, the Mo₂Ti₂C₃T_x substrate achieved prolonged cycling stability of approximately 544 cycles with coulombic efficiency of ~99.79% at high current density of 3 mA cm^-2 and capacity of 1 mAh cm^-2. In full cells, the Mo₂Ti₂C₃T_x anode, paired with an NCM622 cathode, maintained capacity retention of 70% over 100 cycles with high cathode loading of 10 mg cm^-2. Our approach highlights the potential of Mo-based MXenes to improve the performance of lithium metal batteries, making them promising candidates for the next-generation energy storage system.

With the advantages of simple preparation, cost-effectiveness, abundant raw materials, and environmentally friendly properties, hard carbon is the only commercially available anode material for sodium-ion batteries. However, its unstable capacity is attributed to the complex physicochemical characteristics of the precursors, the intricate and difficult-to-control microstructure, and the debated mechanisms of sodium storage. Although recent reports have revealed a strong correlation between closed pores and the capacity of hard carbon in the low-voltage plateau region, systematic overviews of this relationship remain scarce. This review examines the microstructural properties and precursor selectivity of hard carbon materials and outlines the strategies for the research and development of closed pores, including design theory and characterization. Finally, it summarizes the technical bottlenecks faced by the closed pore research and looks forward to the future development directions.

The use of aqueous electrolytes and Zn metal anodes in Zn-based energy storage systems provides several benefits, including competitive energy density, excellent safety, and low cost. However, Zn dendrites growth and slow ion transfer at the electrode/electrolyte interphase reduce the cycle stability and rate capability of the Zn anode. Herein, the V₂O_5-x interface layer was rationally and controllably constructed on the Zn surface through in situ spontaneous redox reaction between V₂O₅ and the Zn anode. The V₂O_5-x interface layer, with an optimized thickness, plays a crucial role in ion screening and de-solvation, leading to a uniform dispersion of Zn²⁺ ions and dendrite-free morphology. Moreover, as Zn²⁺ transports through the V₂O_5-x interface layer, the V element in a low-valence state allows the oxygen anions to bind more easily with Zn²⁺. This interaction enables a fast Zn²⁺ diffusion channel in the interfacial layer. Consequently, symmetric cells with V@Zn anodes achieve stable plating/stripping for more than 1,400 h at 1 mA cm^-2. In particular, the full cell paired with a V₂O₅ cathode exhibits a capacity of nearly 275.9 mA h g^-1 at 5 A g^-1 after 2,500 cycles without obvious capacity deterioration, further highlighting the potential for practical applications.

Composite polymer electrolytes that incorporate ceramic fillers in a polymer matrix offer mechanical strength and flexibility as solid electrolytes for lithium metal batteries. However, fast Li⁺ transport between polymer and Li⁺-conductive filler phases is not a simple achievement due to high barriers for Li⁺ exchange across the interphase. This study demonstrates how modification of Li₇La₃Zr₂O₁₂ (LLZO) nanofiller surfaces with silane chemistries influences Li⁺ transport at local and global electrolyte scales. Anhydrous reactions covalently link amine-functionalized silanes [(3-aminopropyl)triethoxysilane (APTES)] to LLZO nanoparticles, which protects LLZO in air. APTES functionalization lowers the poly (ethylene oxide) (PEO)-LLZO interphase resistance to half that of unmodified LLZO and increases effective Li⁺ transference number, while insulating Al₂O₃ completely blocks ion exchange and lowers transference number and conductivity in PEO-lithium bis(trifluoromethanesulfonyl)imide (LiTFSI)-LLZO composites. Modeling an inner resistive interphase between LLZO and PEO surrounded by an outer conductive interphase explains non-linear conductivity trends. Solid-state ⁷Li & ⁶Li nuclear magnetic resonance shows Li⁺ only exchanges between PEO-LiTFSI and some LLZO interphase, with no appreciable Li⁺ transport through bulk LLZO. Surface functionalization is a promising path toward lowering the polymer-ceramic interphase resistance. This work demonstrates that local changes in Li⁺ transport affect macroscopic performance, highlighting the intricate relationships between all interfaces in inherently heterogeneous composite polymer electrolytes.