Pristine tin (Sn) and tin dioxide (SnO₂) have sparked wide interest owing to their abundant resources and superior theoretical capacity. Nevertheless, the obvious volume expansion effect upon cycling and undesirable conductivity of Sn-based materials lead to undesirable specific capacity. In this work, a nanostructured Sn/SnO₂/nitrogen-doped carbon (NC) superstructure was prepared through a facile electrospray-carbonization strategy. The Sn/SnO₂ nanoparticles (NPs) were uniformly dispersed in a spherical NC matrix, which prevented the volume expansion and aggregation of NPs and facilitated the ion diffusion and charge transfer kinetics. When the optimized Sn/SnO₂/NC superstructures were employed as lithium-ion battery anodes, a remarkable specific capacity of 747.9 mAh·g⁻¹ over 200 cycles at 0.5 A·g⁻¹ and a superior cyclability of 644.1 mAh·g⁻¹ over 1000 cycles at 2 A·g⁻¹ were obtained. This effective synthetic strategy for synthesizing superstructures provides valuable insights for the advancement of lithium-ion batteries.

With the exhaustion of conventional fossil fuels, the exploration of green and sustainable energy will become an important topic of social development. Hydrogen is considered a clean and effective energy source, and its combustion produces only water, which is harmless to the environment. Photocatalytic water splitting, which utilizes solar energy and produces H₂ and O₂, can become a very important reaction for alleviating energy shortages and environmental pollution. Water splitting includes the reduction and oxidation half-reactions, among which the oxidation half-reaction is the rate-determining process. Even though current studies mainly focus on the H₂ or O₂ evolution reactions in the presence of sacrificial agents, overall water splitting remains a challenging problem. Metal–organic frameworks (MOFs) and their precursors have been attracting increasing attention as photocatalysts for water splitting. This paper reviews the research progress in MOFs for photocatalytic overall water splitting and discusses the development prospects and challenges of MOFs. In this study, the research progress in MOF-based water-splitting catalysts for photocatalysis and electrocatalysis is systematically reviewed. Herein, MOF-based catalysts are classified into MOFs, MOF composites, and MOF-derived photocatalysts. We also analyze the prospects and challenges in the preparation of efficient and stable MOF photocatalysts for overall water splitting and propose the construction of new efficient MOFs with double active sites, aiming to improve the efficiency of photocatalytic hydrogen and oxygen evolution to achieve the overall water splitting.

Uncontrollable dendrite growth and side reactions resulting in short operating life and low Coulombic efficiency have severely hindered the further development of aqueous zinc-ion batteries (AZIBs). In this work, we designed to grow zeolitic imidazolate framework-8 (ZIF-8) uniformly on CuO nanosheets (NSs) and prepared carbon-coated CuZn alloy NSs (CuZn@C NSs) by calcination under H₂/Ar atmosphere. As reflected by extended X-ray absorption fine structure (EXAFS), density functional theory (DFT), and in-situ Raman, the Cu–Zn and Zn–N bonds present in CuZn@C NSs act as zincophilic sites to uniformly absorb Zn ions and inhibit the formation of Zn dendrites. At the same time, CuZn@C NSs hinder the direct contact between zinc anode and electrolyte, preventing the occurrence of side reactions. More impressively, the symmetric cells constructed with CuZn@C NSs anodes exhibited excellent zinc plating/exfoliation performance and long life cycle at different current densities with low voltage hysteresis. In addition, low polarization, high capacity retention, and long cycle life over 1000 cycles at 5 A∙g⁻¹ were achieved when CuZn@C NSs were used as anodes for CuZn@C/V₂O₅ full cells.

Although metal–organic frameworks have been heavily tested as the anode materials for lithium-ion batteries (LIBs), the poorer conductivity, easy collapse of frameworks, and serious volume expansion limit their further application in LIBs. Herein, we report a facile approach to obtain MXene-encapsulated porous Ni-naphthalene dicarboxylic acid (Ni-NDC) nanosheets by hybridizing ultrathin Ti₃C₂ MXene and three-dimensional (3D) Ni-NDC nanosheet aggregates. In the structure of Ni-NDC/MXene hybrids, the interlayer hydrogen-bond interaction between Ni-NDC and MXene can effectively increase the interlayer spacing and further inhibit the oxidation of pure MXene. Hence, the introduction of MXene (a conductive matrix) could further improve the conductivity of Ni-NDC, avoid self-agglomeration, and buffer the volume expansion of Ni-NDC nanosheets. Benefiting from the synergistic effects between Ni-NDC and MXene, Ni-NDC/MXene hybrid electrode exhibits a reversible discharge capacity (579.8 mA∙h∙g⁻¹ at 100 mA∙g⁻¹ after 100 cycles) and good long-term cycling performance (310 mA∙h∙g⁻¹ at 1 A∙g⁻¹ after 500 cycles).

Activated graphene (AG) with various specific surface areas, pore volumes, and average pore sizes is fabricated and applied as a matrix for sulfur. The impacts of the AG pore structure parameters and sulfur loadings on the electrochemical performance of lithium-sulfur batteries are systematically investigated. The results show that specific capacity, cycling performance, and Coulombic efficiency of the batteries are closely linked to the pore structure and sulfur loading. An AG3/S composite electrode with a high sulfur loading of 72 wt.% exhibited an excellent long-term cycling stability (50% capacity retention over 1, 000 cycles) and extra-low capacity fade rate (0.05% per cycle). In addition, when LiNO₃ was used as an electrolyte additive, the AG3/S electrode exhibited a similar capacity retention and high Coulombic efficiency (~98%) over 1, 000 cycles. The excellent electrochemical performance of the series of AG3/S electrodes is attributed to the mixed micro/mesoporous structure, high surface area, and good electrical conductivity of the AG matrices and the well-distributed sulfur within the micro/mesopores, which is beneficial for electrical and ionic transfer during cycling.