The intensifying challenges posed by climate change and the depletion of fossil fuels have spurred concerted global efforts to develop alternative energy storage solutions. Aqueous zinc-ion batteries (AZIBs) have emerged as promising candidates for large-scale electrochemical energy storage systems because of their intrinsic safety, cost-effectiveness, and environmental sustainability. However, Zn dendrite growth consistently poses a remarkable challenge to the performance improvement and commercial viability of AZIBs. The use of three-dimensional porous Zn anodes instead of planar Zn plates has been demonstrated as an effective strategy to regulate the deposition/stripping behavior of Zn²⁺ ions, thereby inhibiting the dendrite growth. Here, the merits of porous Zn anodes were summarized, and a comprehensive overview of the recent advancements in the engineering of porous Zn metal anodes was provided, with a particular emphasis on the structural orderliness and critical role of porous structure modulation in enhancing battery performance. Furthermore, strategic insights into the design of porous Zn anodes were presented to facilitate the practical implementation of AZIBs for grid-scale energy storage applications.

With the rapid growth in renewable energy, researchers worldwide are trying to expand energy storage technologies. The development of beyond-lithium battery technologies has accelerated in recent years, amid concerns regarding the sustainability of battery materials. However, the absence of suitable high-performance materials has hampered the development of the next-generation battery systems. MXenes, a family of 2D transition metal carbides and/or nitrides, have drawn significant attention recently for electrochemical energy storage, owing to their unique physical and chemical properties. The extraordinary electronic conductivity, compositional diversity, expandable crystal structure, superior hydrophilicity, and rich surface chemistries make MXenes promising materials for electrode and other components in rechargeable batteries. This report especially focuses on the recent MXene applications as novel electrode materials and functional separator modifiers in rechargeable batteries beyond lithium. In particular, we highlight the recent advances of surface and structure engineering strategies for improving the electrochemical performance of the MXene-based materials, including surface termination modifications, heteroatom doping strategies, surface coating, interlayer space changes, nanostructure engineering, and heterostructures and secondary materials engineering. Finally, perspectives for building future sustainable rechargeable batteries with MXenes and MXene-based composite materials are presented based upon material design and a fundamental understanding of the reaction mechanisms.

MXene, a family of two-dimensional (2D) transition metal carbides and nitrides have attracted extensive interests for many biochemical applications, including tumour elimination, biosensors, and magnetic resonance imaging (MRI). In this article, we firstly discovered that Ti₃C₂T_x MXene exhibited a highly efficient adsorption capability as hemoperfusion absorbent towards middle-molecular mass and protein bound uremic toxins in the end stage of renal disease (ESRD) treatment. Molecular scale investigations reveal that the high efficiency of MXene for the removal of uremic toxins could be attributed to synergistic effects of physical/chemical adsorption, electrostatic interaction surface of 2D MXene, and transformation of protein secondary structure. 2D MXene materials could be used as a new hemoperfusion sorbent with ultrahigh efficiency for removing uremic toxins during the treatment of kidney disease.

Sodium metal is one of the ideal anodes for high-performance rechargeable batteries because of its high specific capacity (~ 1166 mAh·g⁻¹), low reduction potential (−2.71 V compared to standard hydrogen electrodes), and low cost. However, the unstable solid electrolyte interphase, uncontrolled dendrite growth, and inevitable volume expansion hinder the practical application of sodium metal anodes. At present, many strategies have been developed to achieve stable sodium metal anodes. Here, we systematically summarize the latest strategies adopted in interface engineering, current collector design, and the emerging methods to improve the reaction kinetics of sodium deposition processes. First, the strategies of constructing protective layers are reviewed, including inorganic, organic, and mixed protective layers through electrolyte additives or pretreatments. Then, the classification of metal-based, carbon-based, and composite porous frames is discussed, including their function in reducing local deposition current density and the effect of introducing sodiophilic sites. Third, the recent progress of alloys, nanoparticles, and single atoms in improving Na deposition kinetics is systematically reviewed. Finally, the future research direction and the prospect of high-performance sodium metal batteries are proposed.

The electrical energy that can be harnessed from the salinity difference across the sea water and river water interface can be one of the sustainable and clean energy resources of the future. This energy can be harnessed via the nanofluidic channels that selectively permeate ions. The selective diffusion of cations and anions can produce electricity through reverse electrodialysis. Two-dimensional (2D) materials are a class of nanomaterials that hold great promise in this field. Several breakthrough works have been previously published which demonstrate the high electrical power densities of 2D membranes. The ion transportation can be either through the nano-sized in-plane pores or interlayer spacings of 2D materials. This review article highlights the progress in 2D materials for salinity gradient power generation. Several types of 2D membranes with various nano-architectures are discussed in this review article. These include atom-thick 2D membranes with nanopores, 2D lamellar membranes, 2D lamellar membranes with nanopores, 2D/one-dimensional (1D), and 2D/2D hybrid membranes. The fabrication techniques, physical characteristics, ion transportation properties, and the osmotic power generation of these 2D membranes are elaborated in this review article. Finally, we overview the future research direction in this area. It is envisioned that the research on 2D materials can make practical salinity gradient power generation one step closer to reality.

Lithium-rich oxide compounds have been recognized as promising cathode materials for high performance Li-ion batteries, owing to their high specific capacity. However, it remains a great challenge to achieve the fully reversible anionic redox reactions to realize high capacity, high stability, and low voltage hysteresis for lithium-rich cathode materials. Therefore, it is critically important to comprehensively understand and control the anionic redox chemistry of lithium-rich cathode materials, including atomic structure design, and nano-scale materials engineering technologies. Herein, we summarize the recent research progress of lithium-rich cathode materials with a focus on redox chemistry. Particularly, we highlight the oxygen-based redox reactions in lithium-rich metal oxides, with critical views of designing next generation oxygen redox lithium cathode materials. Furthermore, we purposed the most promising strategies for improving the performances of lithium-rich cathode materials with a technology-spectrum from the atomic scale to nano-scale.

The rapid development of portable, foldable, and wearable electronic devices requires flexible energy storage systems. Sodium-ion capacitors (SICs) combining the high energy of batteries and the high power of supercapacitors are promising solutions. However, the lack of flexible and durable electrode materials that allow fast and reversible Na⁺ storage hinders the development of flexible SICs. Herein, we report a high-capacity, free-standing and flexible Sb₂S₃/Ti₃C₂T_x composite film for fast and stable sodium storage. In this hybrid nano-architecture, the Sb₂S₃ nanowires uniformly anchored between Ti₃C₂T_x nanosheets not only act as sodium storage reservoirs but also pillar the two-dimensional (2D) Ti₃C₂T_x to form three-dimensional (3D) channels benefiting for electrolyte penetration. Meanwhile, the highly conductive Ti₃C₂T_x nanosheets provide rapid electron transport pathways, confine the volume expansion of Sb₂S₃ during sodiation, and restrain the dissolution of discharged sodium polysulfides through physical constraint and chemical absorption. Owing to the synergistic effects of the one-dimensional (1D) Sb₂S₃ nanowires and 2D MXenes, the resultant composite anodes exhibit outstanding rate performance (553 mAh·g⁻¹ at 2 A·g⁻¹) and cycle stability in sodium-ion batteries. Moreover, the flexible SICs using Sb₂S₃/Ti₃C₂T_x anodes and active carbon/reduced graphene oxide (AC/rGO) paper cathodes deliver a superior energy and power density in comparison with previously reported devices, as well as an excellent cycling performance with a high capacity retention of 82.78% after 5,000 cycles. This work sheds light on the design of next-generation low-cost, flexible and fast-charging energy storage devices.

Recently, Prussian blue and its analogues (PBAs) have attracted tremendous attention as cathode materials for sodium-ion batteries because of their good cycling performance, low cost, and environmental friendliness. However, they still suffer from kinetic problems associated with the solid-state diffusion of sodium ions during charge and discharge processes, which leads to low specific capacity and poor rate performances. In this work, novel sodium iron hexacyanoferrate nanospheres with a hierarchical hollow architecture have been fabricated as cathode material for sodium-ion batteries by a facile template method. Due to the unique hollow sphere morphology, sodium iron hexacyanoferrate nanospheres can provide large numbers of active sites and high diffusion dynamics for sodium ions, thus delivering a high specific capacity (142 mAh/g), a superior rate capability, and an excellent cycling stability. Furthermore, the sodium insertion/extraction mechanism has been studied by in situ X-ray diffraction, which provides further insight into the crystal structure change of the sodium iron hexacyanoferrate nanosphere cathode material during charge and discharge processes.

Faceted crystals with exposed highly reactive planes have attracted intensive investigations for applications. Herein, we demonstrate a general synthetic method to prepare mesocrystal Co₃O₄ with predominantly exposed {111} reactive facets by the in situ thermal decomposition from Co(OH)₂ nanoplatelets. The mesocrystal feature was identified by field emission scanning electron microscopy, transmission electron microscopy, selected area electron diffraction, and N₂ isotherm analyses. When applied as anode material in lithium-ion batteries, mesocrystal Co₃O₄ nanoplatelets delivered a high specific capacity and an outstanding high rate performance. The superior electrochemical performance should be ascribed to the predominantly exposed {111} active facets and highly accessible surfaces. This synthetic strategy could be extended to prepare other mesocrystal functional nanomaterials.