MXene materials have emerged as promising candidates for solving sustainable energy storage solutions due to their unique properties and versatility. MXene materials can not only be used directly as electrode materials but can also be used as functional materials to solve problems such as poor conductivity of electrode materials, severe volume expansion, dendrites, and dissolution of electrode materials. This perspective paper explores the potential applications of MXene materials for sustainable energy storage solutions, emphasizing their distinct characteristics and applications across various domains.

Carbon-based materials have been found to accelerate the sluggish kinetic reaction and are largely subject to the overall Zn-air batteries (ZABs) property, while their full catalytic mechanism is still not excavated because of the indistinct internal structure and immature in-situ technology. Up to now, systematic methods have been utilized to study and design promising high-performance carbon-based catalysts. To resolve the real active units and catalytic mechanism, developing molecular catalyst is a significant strategy. Herein, the review will initiate to briefly introduce the working principle and composition of ZABs. An important statement is correspondingly provided about the typical structure and catalytic mechanisms for the air cathode material. It also presents the tremendous endeavors on the catalytic performance and stability of carbon-based material. Furthermore, combined with theoretical calculation, the self-defined active sites are analyzed to understand the catalytic character, where the molecular catalyst is subsequently summarized and discussed through highlighting the unambiguous and controllable structure, in the hope of surfacing the optimum catalyst. Building on the fundamental understanding of carbon-based and molecular catalysts, this review is expected to provide guidance and direction toward designing future mechanistic studies and ORR electrocatalysts.

The extensive consumption of chicken has resulted in the emergence of a significant environmental issue in the form of chicken feather waste. As such, there is an urgent need for the development of green treatment and recycling methods for chicken feathers. Chicken feathers can serve as a type of heteroatomic doping carbon source, making them an excellent candidate for the electrode materials used in electrochemical energy devices. Furthermore, their unique structures and functional groups make them highly promising for use as adsorbents, electronics, and building materials. In this paper, we provide a summary and review of recent progress made in the use of chicken feathers for energy and environmental applications. Based on the theoretical knowledge and practical applications presented in this review, promising green recycling processes of chicken feathers can be developed. These processes can help to reduce environmental pollution and promote sustainable development.

Currently, the concentration of carbon dioxide (CO₂) has exceeded 400 ppm in the atmosphere. Thus, there is an urgent need to explore CO₂ reduction and utilization technologies. Photocatalytic technology can convert CO₂ to valuable hydrocarbons (CH₄, CH₃OH, and C₂H₅OH, etc.), realizing the conversion of solar energy to chemical energy as well as solving the problems of fossil fuel shortage and global warming. Graphitic carbon nitride (g-C₃N₄), as a two-dimensional nonmetallic semiconductor material, shows great potential in the field of CO₂ photoreduction due to its moderate bandgap, easy synthesis method, low cost, and visible light response properties. This review elaborates the research progress of g-C₃N₄-based photocatalysts for photocatalytic CO₂ reduction. The modification strategies (e.g., morphology engineering, elemental doping, crystallinity modulation, cocatalyst modification, and constructing heterojunction) of g-C₃N₄-based photocatalysts for CO₂ reduction application have been discussed in detail. Finally, the challenges and development prospects of g-C₃N₄-based photocatalytic materials for CO₂ reduction are presented.

The cycling stability of O3-type NaNi_1/3Fe_1/3Mn_1/3O₂ (NFM) as a commercial cathode material for sodium ion batteries (SIBs) is still a challenge. In this study, the Ni/Fe/Mn elements are replaced successfully with tantalum (Ta) in the NFM lattice, which generated additional delocalized electrons and enhanced the binding ability between the transition metal and oxygen, resulting in suppressed lattice distortion during charging and discharging. This caused significant mitigation of voltage decay and improved cycle stability within the potential range of 2.0–4.2 V. The optimized Na(Ni_1/3Fe_1/3Mn_1/3)_0.97Ta_0.03O₂ sample achieved a reversible capacity of 162.6 mAh g^-1 at a current rate of 0.1 C and 73.2 mAh g^-1 at a high rate of 10 C. Additionally, the average charge/discharge potential retention reached 98% after 100 cycles, significantly mitigating the voltage decay. This work demonstrates a significant contribution towards the practical utilization of NFM cathodes in the SIBs energy storage field.

Lithium metal solid-state battery is the first choice of batteries for electromobiles and consumer electronic products because of the specific capacity of 3860 mAh g^-1 and high electrochemical potential (-3.04 V) of Li metal. Flexible polymer solid electrolytes have become the optimal solution to produce high energy density lithium batteries with arbitrary size and shape. In this work, we introduce a halide perovskite, CsSnI₃, into the polyethylene oxide/lithium bis-(trifluoromethanesuphone)imide (PEO–LiTFSI) polymer matrix. The CsSnI₃ could form a Li_xSn alloy with Li, leading to homogenization of the electric field and Li⁺-flux at the interface, Sn atom also bonds with the TFSI^- anion to provide more dissociated Li⁺. Besides that, the I atom could interact with Li to form an electronic insulation with a strong blocking effect on electron tunneling. As a proof of concept, the synergy mechanism of the PEO–LiTFSI–CsSnI₃ electrolyte improves the stable cycle life of the symmetric battery to more than 500 h, and the Li⁺ conductivity raised to 6.1 × 10^-4S cm^-1 at 60°C. The application of the “zwitter ions analog” halide perovskite in PEO–LiTFSI provides a new choice among various methods to improve the electrochemical performance of polymer solid-state batteries.

The high-value utilization of blast furnace slag (BFS) and steel slag (SS) as a valuable resource in the field of carbon reduction represents a green revolution, and also is an indispensable path toward breaking through resource and environmental constraints and achieving high-quality, sustainable development through solid waste utilization in the steel industry. Achieving resource recycling while harnessing the untapped latent energy of resources and exploring their carbon sequestration capabilities has become a crucial avenue for further valorization through waste utilization. BFS and SS discharged from iron-making or steel-making furnaces carry a significant amount of latent heat, especially the calcium oxide component in SS, which gives it a unique advantage in the field of comprehensive BFS and SS utilization and carbonation-based SS utilization. This article discusses the current research status of low-carbon-waste-heat utilization in the production of microcrystalline glass, cementitious materials, functional adsorbents, and other products through front-end modification of molten BFS and SS. This report also provides an overview of carbon capture by utilizing BFS and SS, offering insights into the research directions for subsequent heat recovery, online quality adjustment, high-value utilization, and carbon sequestration using BFS and SS in the steel industry.

Anode-free rechargeable batteries (AFRBs), equipped with bare collectors at the anode, are potential electrochemical energy storage technology attributed to their simplified cell configuration, high energy density, and cost reduction. Nevertheless, issues including insufficient Coulombic efficiency as well as the formation of the dendrites restrict their practical implementation. In recent years, various strategies have been proposed to overcome the critical issues of AFRBs. Among which, interfacial properties play key roles for achieving high stable AFRBs. In this review, an overview of AFRBs is discussed in the first part. Then, the main strategies based on interfacial regulation engineering toward high-performance AFRBs are summarized including designing of current collectors, introducing of surface coating layers, modification of electrolytes, separators engineering, cathode materials regulation, and so forth. In addition, some future perspectives for developing AFRBs are proposed. This review will create new avenues on constructing stable AFRBs for advanced energy storage devices.

Li metal batteries have been widely expected to break the energy-density limits of current Li-ion batteries, showing impressive prospects for the nextgeneration electrochemical energy storage system. Although much progress has been achieved in stabilizing the Li metal anode, the current Li electrode still lacks efficiency and safety. Moreover, a practical Li metal battery requires a thickness-controllable Li electrode to maximally balance the energy density and stability. However, due to the stickiness and fragile nature of Li metal, manufacturing Li ingot into thin electrodes from conventional approaches has historically remained challenging, limiting the sufficient utilization of energy density in Li metal batteries. Aiming at the practical application of Li metal anode, the current issues and their initiation mechanism are comprehensively summarized from the stability and processability perspectives. Recent advances in robust and ultra-thin Li metal anode are outlined from methodology innovation to provide an overall insight. Finally, challenges and prospective developments regarding this burgeoning field are critically discussed to afford future outlooks. With the development of advanced processing and modification technology, we are optimistic that a truly great leap will be achieved in the foreseeable future toward the industrial application of Li metal batteries.

Biomass-derived carbon as energy storage materials have gradually attracted widespread attention due to their low cost, sustainability, and inherent structural advantages. Herein, hard carbon (H-1200) and porous carbon (PC-800) for sodium-ion batteries (SIBs), sodium-ion capacitors (SICs) half cells and sodium-ion hybrid capacitors (SIHCs) have been synthesized from the same biomass precursor of Camellia shells through different treatments. H-1200 synthesized by directly high-temperature carbonization possesses a rational graphitic layer structure and plentiful heteroatoms. When applied as anode for SIBs, it exhibits a reversible capacity of 365.5 mAh g^-1 at 25 mA g^-1 and capacity retention 89.0% after 400 cycles at 200 mA g^-1. Additionally, PC-800 prepared by catalytic carbonization of K₂C₂O₄/CaC₂O₄ hybrid catalyst has a sophisticated porous structure and a high surface area of 2186.9 m² g^-1. When employed as a cathode for SICs, it delivers a maximum capacity 104.2 mAh g^-1 at 100 mA g^-1 and 35.0 mAh g^-1 at 5 A g^-1. Furthermore, the all carbon assembled SIHC (H-1200||PC-800) using H-1200 as anode and PC-800 as cathode, features a broad output voltage range (0.01 ~ 4.1 V), high energy density of 161.5Wh kg^-1, power density of 12896.1Wkg^-1, and superior capacity retention of 90.32% after 10000 cycles at 10 A g^-1. This research result provide a new horizon for constructing low-cost and large-scale production of biomass derived carbon for energy storage materials.

The development of cathode materials with controllable physicochemical structures and explicit catalytic sites is important in rechargeable Zn–air batteries (ZABs). Covalent organic frameworks (COFs) have garnered increasing attention owing to their facile synthesis methods, ordered pore structure, and selectivity of functional groups. However, the sluggish kinetics of oxygen evolution reaction (OER) or oxygen reduction reaction (ORR) inhibit their practical applications in ZABs. Herein, nucleophilic substitution is adopted to synthesize pyridine bi-triazine covalent organic framework (denoted as O-COF), and meanwhile, ionothermal conversion synthesis is employed to load MO_x (M=Fe, Co) onto carbon nanosheet (named as FeCo@NC) to modulate the electronic structure. The Fe, Co-N codoped carbon material possesses a large portion of pyridinic N and M-N, high graphitization, and a larger BET surface area. An outstanding bifunctional activity has been exhibited in FeCo@NC, which provides a small voltage at 10 mAcm^-2 for OER (E₁₀ = 1.67 V) and a remarkable half-wave voltage for ORR (E_1/2 = 0.86 V). More impressively, when assembling ZABs, it displays notable rate performance, significant specific capacity (783.9 mAh gZn^-1), and satisfactory long-term endurance. This method of regulating covalent organic framework and ionothermal synthesis can be extended to design diverse catalysts.

Two-dimensional (2D) semiconductors, such as monolayer MoS₂, has emerged as a profound material platform in the post-Moore era due to their versatile applications for high-performance transistors, memories, photodetectors, neuristors, and so on. Nevertheless, the inherent defects in these atomically thin materials have given rise to significant hysteresis in their field-effect transistors (FETs), resulting in shifted threshold voltages and elevated power consumptions not only on single-device levels but also at circuitry scales. We herein report that, by vertically integrating an in-plane ferroelectric, NbOCl₂, with monolayer MoS₂ FETs, the hysteresis in both the output and transfer curves of the latter can be greatly suppressed, which we attribute to compensated electromigration currents by the polarization currents of the 2D ferroelectric. This work opens a new avenue to hysteresis-free 2D transistors without necessitating defect-free channels, thus allowing for their use in high driving-voltage scenarios such as power electronics.

Anion exchange membrane fuel cells (AEMFCs) have been hailed as a promising hydrogen energy technology due to high energy conversion efficiency, zero carbon emission and the potential independence on scare and expensive noble metal electrocatalysts. A variety of platinum group metal (PGM)-free catalysts has been developed with superior catalytic performance to noble metal benchmarks toward cathodic oxygen reduction reactions (ORR). However, PGM electrocatalysts still dominate the anodic catalyst research because the kinetics of hydrogen oxidation reaction (HOR) are two or three orders of magnitude slower than in that acidic media. Therefore, it is urgently desirable to improve noble metal utilization efficiency and/or develop high-performance PGM-free electrocatalysts for HOR, thus promoting the real-world implementation of AEMFCs. In this review, the current research progress of electrocatalysts for HOR in alkaline media is summarized. We start with the discussion on the current HOR reaction mechanisms and existing controversies. Then, methodologies to improve the HOR performance are reviewed. Following these principles, the recently developed HOR electrocatalysts including PGM and PGM-free HOR electrocatalysts in alkaline media are systematically introduced. Finally, we put forward the challenges and prospects in the field of HOR catalysis.

Photocatalysis is an environmentally friendly technology for the utilizations of solar energy and has garnered significant attention in both scientific and industrial sectors. Developing cost-effective semiconductive materials is the core issue in photocatalysis. Bismuth-based metal-organic frameworks (Bi-MOFs) have emerged as attractive candidates in various photocatalytic applications, and Bi-MOFs derivatives further expand and consolidate their promising potential in the realm of photocatalysis. Various modification strategies including in-situ tailoring or external doping, as well as meticulous design and selection of metal nodes and organic linkers allow for fine control over the surface multifunctionality in Bi-MOF-based and derived photocatalytic composites with adjustable energy band structures and enhanced photocatalytic performance. In this review, the recent progress in the synthesis of diverse Bi-MOFs-based materials, Bi-MOFs derivatives, and their Bi-containing semiconductive composites were systemically analyzed and reviewed. The state-of-the-art research progresses in the applications of Bi-MOFs and derivatives, as well as composites in photocatalytic water splitting for hydrogen production, photodegradation of organic pollutants, and photocatalytic carbon dioxide reduction are comprehensively summarized. The relationships between structures, properties, and photocatalytic performance of Bi-based semiconductive composites are discussed in detail. In addition, the perspectives and future challenges on Bi-MOFs-based and derived materials for photocatalytic applications are also offered.