Advanced lithium-gas batteries (LGBs), including Li-CO2 batteries (LCOBs), Li-O2 batteries (LOBs), and Li-N2 batteries (LNBs) systems, offer superior energy density and promising long-term stability. However, their widespread implementation is hindered by slow gas-conversion kinetics, causing high overpotentials, low-rate performance, and limited electrochemical reversibility, which severely affects cycling stability. Addressing these challenges requires designing bifunctional electrocatalysts that enhance both discharge and charge reactions for efficient gas conversion. Carbon-based metal-free electrocatalysts (C-MFECs) and carbon-supported single-atom catalysts (CS-SACs) are highly promising alternatives, distinguished by their outstanding catalytic activity for efficient reactant activation and product decomposition. This review offers an in-depth analysis of LGBs, discussing the key challenges that hinder gas-conversion reversibility and emphasizing the origin of bifunctional catalytic activity in C-MFECs and CS-SACs. We further explore recent advances in LGB applications, highlighting strategies to improve catalytic efficiency and electrochemical reversibility. Finally, we outline future directions for developing bifunctional C-MFECs and CS-SACs, focusing on material innovation, mechanistic insights, and practical implementation to drive the development of sustainable next-generation LGBs.

Abstract The commercial viability of room-temperature sodium-sulfur (RT-Na/S) batteries remains primarily hindered by the shuttle effect and the sluggish redox kinetics of the sulfur reduction reaction (SRR). The heterostructure materials are promising electrocatalyst candidates that empower advanced RT-Na/S batteries. Herein, we report a cathode design that uses the MoS2/C12A7:e− electride heterostructure as a sulfur cathode host to address these issues. Based on density functional theory (DFT) and molecular dynamics (MD) simulations, we find that coupling MoS2 with highly conductive C12A7:e− significantly enhances the cathode-host functionality beyond that of the pristine MoS2. The presence of C12A7:e− induces atomic rearrangements in MoS2, which consequently modulates the surface polarity of exposed S atoms, thereby strengthening the interaction with the Na atoms in heteropolar sodium polysulfides (Na2Sn; n = 1, 2, 4, 6, 8). The resulting Na─S chemisorption between Na2Sn species and the MoS2/C12A7:e− heterostructure is sufficiently strong to exceed Na2Sn−electrolyte interactions, effectively suppressing polysulfide dissolution and mitigating the shuttle effect. Electronic structure analysis further reveals that the enhanced chemisorption originates from pronounced Na-3s and S-3p orbital interactions. Importantly, this intensified host−polysulfides interaction also promotes the SRR by lowering the Gibbs free-energy changes during Na2Sn conversion. These theoretical findings propose the MoS2/C12A7:e− heterostructure as a potential bifunctional cathode host that simultaneously immobilizes sodium polysulfides and accelerates sulfur redox kinetics in RT-Na/S batteries.

The transition to sustainable, high‐performance alternatives to lithium‐ion systems is accelerating research progress in electrochemical energy storage. Cellulose‐derived carbons, made from abundant, renewable biomass, are emerging as promising candidates, offering natural environmental friendliness, adjustable structure, and functional versatility. This review examines the hierarchical architecture of cellulose, its carbonization pathways, and the influence of extraction and processing methods on precursor properties. Advances in synthetic techniques, from heteroatom doping to creating composite hybrids, are discussed for their role in controlling porosity, conductivity, and electrochemical behavior. Structure‐property relationships and function of these carbons are analyzed in the context of sodium‐, potassium‐, zinc‐, and magnesium‐ion batteries, as well as hybrid supercapacitors. Important material properties, including electrical conductivity, mechanical strength, thermal stability, and morphological control, are analyzed in relation to device performance. Challenges related to scalability, electrolyte compatibility, and cycle life are addressed, with a focus on sustainable synthesis and integration routes. This review uniquely integrates cellulose‐derived carbon across multiple postlithium energy storage systems with a focus on scalable synthesis and electrochemical optimization.

The unavailability of high-performance cathodes hinders large-scale adoption of sodium-ion batteries (NIBs). In this work, we report for the first time a Leidenfrost-assisted synthesis as a low-cost and scalable approach for designing In3+-doped mixed phosphate ([PO4]3--[P2O7]4-) cathodes. The strategic substitution of In3+ at the Fe site induces lattice expansion, thereby facilitating enhanced Na+ diffusion and improved electrochemical performance. The optimized cathode composition, Na4Fe2.97In0.03(PO4)2P2O7 (NFIPP03), exhibits exceptional electrochemical performance, with a specific capacity of 129.3 mAh g-1 at 0.05 C, corresponding to an energy density of ∼ $\sim $ 359 Wh kg-1, and a stable cycling performance more than 10 000 cycles at 20 C. Temperature-dependent magnetic susceptibility (M-T) and electron paramagnetic resonance (EPR) measurements reveal an enhanced spin state in NFIPP03 compared to the pristine sample, as well as improved electrical conductivity. Ex situ XRD and XPS analyses confirm excellent structural and chemical stability during (de)sodiation. Furthermore, density functional theory (DFT) calculations indicate significantly widened Na+ migration pathways, reduced activation energy barrier, and an attenuated bandgap in NFIPP03 which corroborates our experimental observations. Our findings highlight the synthesis for developing cost-effective, high-performance iron-based mixed-phosphate cathodes, advancing the sustainability and scalability of NIB technology.

The electrochemical conversion of CO2 (CO2RR) offers a promising approach to lowering atmospheric CO2 levels while producing value-added chemicals and fuels. Understanding operating parameters is essential for boosting the CO2RR performance and scaling up electrolyzers, with pressure playing a critical role due to the inherently low solubility of CO2 in aqueous electrolytes. In this work, a techno-economic assessment of a pressurized CO2-to-CO electrolysis system with a membrane electrode assembly configuration is conducted to evaluate the cost drivers and optimization pathways. Increasing operating pressure from 0 to 40 bar significantly reduces the product cost from US$2259/tCO to US$914/tCO, underscoring the economic advantage of pressurization. At elevated pressures, Faradaic efficiency toward CO can also be increased via increasing CO2 excess, though this raises downstream separation costs. The minimum levelized cost of CO is achieved when the CO2 excess is 3.88, corresponding to US$624/tCO. Sensitivity analysis identifies electricity cost as the dominant cost factor. Overall, these findings highlight the economic benefits of pressurized CO2 electrolysis and provide guidance for future research.

Soft robotic systems enable autonomous shape morphing through intrinsically stimuli-responsive materials, marking a significant advance over conventional rigid, component-based robots. While multi-material soft actuators offer functional versatility, they often compromise structural continuity and design simplicity which are central tenets of soft robotics. By contrast, monolithic soft robotic systems (MSRs) employ single-phase or compositionally unified material architectures that embed actuation functionality directly into the material–geometry construct. This review studies key actuation mechanisms, canonical morpho-functional shape archetypes and programmable material platforms that collectively underpin MSR operation. We examine how deformation logic can be encoded into a material via intrinsic property gradients, internal anisotropies and field-responsive domains, thereby enabling scalable, adaptive responses to external stimuli. Finally, we outline key scientific challenges and strategic directions for MSR development, including the integration of embedded intelligence, model-based programmability, fabrication scalability, sustainable material innovation and multifunctional autonomy.

Electrochemical reduction of CO2 (CO2RR) offers a sustainable route for converting renewable electricity into value-added chemicals. However, scaling CO2RR to industrially relevant current densities remains challenging due to intrinsic kinetics barriers, competing side reactions such as the hydrogen evolution reaction (HER), and limitations in CO2 mass transport. To elucidate whether catalyst activity or CO2 availability dominates CO2RR performance across current densities, we engineered flow-through hollow fiber gas diffusion electrodes (HFGDEs) integrated with in-situ grown, defect-rich silver nanosheets. At low current densities, catalytic activity is the primary determinant. The developed HFGDE with defect-rich silver nanosheets yields a high Faradaic efficiency of CO of 93.5 % at-0.8 (V vs. RHE), attributed to enhanced adsorption of *COOH intermediate on silver defect sites, as confirmed by in-situ Raman spectroscopy and density functional theory (DFT) calculations. However, as the system scales to industrially relevant current densities (up to 500 mA/cm2), CO2 availability becomes the dominant limitation due to the intensified fight between CO2 and H2O for electrons. The HFGDE architecture addresses this challenge by continuously supplying convective CO2 flow to the active sites, enabling a CO partial current density of 381.8 mA/cm2 under a total current density of 500 mA/cm2. These findings highlight that while catalyst activity governs CO2RR performance at lower current densities, adequate CO2 supply is essential to maintain high selectivity and suppress HER under industrial conditions.

The development and creation of MXenes, a novel class of two-dimensional (2D) early transition metal carbides and carbonitrides, have demonstrated numerous appealing properties and hold significant potential for energy storage and various other applications. More specifically, Ti3C2 and Ti3C2Tx MXenes (Tx stands for surface terminating species, including O, OH, and F) have garnered widespread attention due to their excellent electrical conductivity, remarkable flexibility, and customisable surface chemistry, making them exceptionally suitable in sensing applications, including strain/stress sensors, gas sensors, and biosensors. Several fabrication processes, including thin film deposition, hydrogel synthesis, and composite integration, have been explored to enhance sensor performance and stability. Specifically, their higher surface area and metallic conductivity make them highly promising candidates for electromagnetic interference (EMI) shielding, as well as energy storage and conversion applications. Next-level approaches, such as surface modification, composite design, and device engineering, are being sought to overcome the challenges related to material stability and its scalability. Through a comprehensive analysis of recent advancements and prospects, this review aims to provide worthy perceptions into the potential of Ti3C2 and Ti3C2Tx MXenes for the development of innovative solutions in spanning sensing, energy, and intelligent robotics fields, with implications for a wide range of industries and scientific research endeavours.

Electrochemical reduction of CO2 (CO2RR) into value-added products offers a promising strategy to reduce dependence on fossil fuels, particularly when powered by renewable electricity. However, CO2RR faces challenges, including high activation energy barriers, competing side reactions, and limited CO2 mass transport. Addressing these limitations requires not only the development of advanced electrocatalysts to enhance CO2RR activity but also the design of electrodes to optimize gas-catalyst-electrolyte interfaces and facilitate efficient mass transport, thereby advancing CO2RR toward industrial-scale applications. Herein, we developed flow-through hollow fiber gas diffusion electrodes (HFGDEs) featuring in situ galvanic growth of flower-like silver structures. The abundant ultrathin 2D nanosheets enhance active sites and CO2RR activity, and the resulting electrode achieves a high Faradaic efficiency of CO of 91% at -1.2 (V vs RHE). Furthermore, the HFGDE configuration ensured sufficient CO2 delivery to the active sites, enabling a partial current density of CO of 280.8 mA cm-2. In situ Raman spectroscopy revealed that the in situ-grown silver flower structure promotes the adsorption of *COOH intermediate, thereby accelerating CO2RR kinetics. Moreover, the robust CO2 supply afforded by the HFGDE configuration is crucial to suppress competitive hydrogen evolution reaction (HER) and maintain high CO2RR activity under industrially relevant current densities.

Aqueous aluminium-ion batteries (AAIBs) have emerged as a promising post-lithium energy storage technology due to their low cost, abundant resources, and inherent safety. This review provides a comprehensive summary of recent advances in AAIBs, focusing on three key aspects: cathode materials, anode engineering, and electrolyte innovation. Among cathode materials, manganese-based oxides, Prussian blue analogues, and organic compounds have shown notable capacities and cycling performance, with manganese dioxides standing out for its rich polymorphs and high electrochemical activity. However, structural instability remains a challenge, prompting the development of in situ electrochemical transformation, heteroatom doping, and electrolyte additive strategies. On the anode side, aluminium (Al) metal suffers from passivation and irreversible reactions in aqueous media, limiting its cycling life. Strategies such as surface pretreatment, amorphization, and alloying have been employed to improve reversibility and interfacial stability. Electrolyte development has progressed from traditional Al salt solutions to highly concentrated Al(OTF)3 systems, deep eutectic solvents, and gel-based formulations, effectively widening the electrochemical stability window and enhancing overall battery performance. Despite significant progress, challenges such as cathode structural degradation and Al anode instability persist. Continued advancements in interfacial engineering and electrolyte design will be crucial to realizing the practical deployment of AAIBs.

The demand for valuable and sustainable chemicals and nonfossil fuels, with a carbon-neutral or zero-carbon footprint from zero-cost, abundant waste streams, has garnered significant interest in recent years. This has been driven by a global desire to transition to a circular economy, by reducing global reliance and eventually the need for fossil-based resources. Hydrothermal carbonization (HTC), a thermal conversion technology, is widely used to recover carbon and energy from waste, avoiding the energy-intensive drying process for high-moisture feedstock, and operating at lower temperatures than conventional processes. The main product, waste-derived hydrochar (WHC), has attracted growing interest in electrochemical energy storage (EES) devices (e.g., rechargeable batteries and supercapacitors) due to its straightforward process, favorable properties, high carbon conversion, and environmental benefits. Hence, this critical review will provide the reader with a better understanding of the principles, technical feasibility, and limitations of carbon conversion from waste through various conversion pathways. Moreover, it presents detailed state-of-the-art studies previously reported on WHC production using one-step direct carbonization (DC) and the two-step HTC followed by DC for electrochemical energy storage applications, with a focus on the role of WHC-based electrodes. Lastly, the challenges and prospects for developing WHC materials for EES applications are examined.

Aqueous Zn-ion batteries (ZIBs) are promising alternatives to lithium-ion batteries because of their inherent safety, raw material abundance (10 million metric tons of zinc in India and Australia is the...

Overcoming the energy density limitations of sodium-ion batteries (NIBs) requires innovative strategies to optimize cathode materials. While entropy-engineering through multi-ion doping has shown promise, previous efforts in polyanion-type cathodes are confined to conventional (pyro)phosphate-based systems. Here, it is reported for the first time a entropy-engineered NASICON-type cathode, NaFe1.8(MnCrAlZnIn)0.2(PO4)(MoO4)2 (NFM'PM20), stabilized in a rare monoclinic P2/c phase via solid-state reaction. This entropy design enables robust cathode-electrolyte interphase (CEI) formation, mitigates lattice strain, and reduces the bandgap, collectively facilitating reversible 2.6 Na+ storage with an exceptional energy density of 315.62 Wh kg-1. The NFM'PM20 cathode demonstrates outstanding cycling stability (92.2% capacity retention after 500 cycles at 5C) and ultra-long cycle life exceeding 2000 cycles. Mechanistic investigations via in situ X-ray diffraction confirm a strain-accommodating solid-solution reaction mechanism with minimal volume change (approximate to 4.5%). At the same time, electron paramagnetic resonance and magnetic susceptibility measurements demonstrate enhanced Fe spin-states, which improve electrontransport. Ex-situ transmission electron microscope images reveal a thin and stable CEI layer. Density functional theory calculations elucidate the atomic-scale advantages, including optimized Na+ migration pathways with 0.45 eV lower diffusion barriers and enhanced interfacial charge transfer kinetics. The NFM'PM20 cathode represents a transformative advancement for developing practical high-energy-density NIBs.

Solar-driven interfacial evaporation systems hold great potential for addressing clean water scarcity and wastewater purification challenges. However, low water yield and the presence of contaminants in wastewater remain significant obstacles. This study introduces wide light-absorbing hydrophilic aminophenol-formaldehyde (APF) resin particles with pi-conjugated and pi-stacked benzenoid-quinoid donor-acceptor couples as light absorbers to enhance solar-to-vapor conversion efficiency. The incorporation of hydrophilic amine groups led to a 30% increase in the evaporation rate and a 32% reduction in the evaporation enthalpy. The carbonized APF-based evaporator achieved a high evaporation rate of 2.89 kg m-2 h-1 and 3.07 kg m-2 h-1 from sewage and simulated seawater, respectively, under natural solar irradiance (0.7 suns). Furthermore, solar vapor generation rates reached 16.22 kg m-2 h-1 and 13.98 kg m-2 h-1 from sewage and simulated seawater under 3.9 suns. The APF-based evaporator also demonstrated exceptional stability and durability in solar-to-vapor conversion.

The availability of CO2 near the active sites is crucial for suppressing hydrogen evolution reaction (HER) and improving the kinetics of electrochemical reduction of CO2 (CO2RR) in aqueous electrolytes at high current density. The hollow fiber gas-diffusion electrodes (HFGDEs) configuration can deliver CO2 continuously to catalyst/electrolyte interfaces without requiring a separate gas chamber, contrasting with planar gas-diffusion electrodes (GDEs). However, the relatively inhomogeneous pore geometry on the surface of HFGDEs leads to poor CO2 distribution, resulting in an increasing number of flooded pores and parasitic HER, especially at high current densities. This work presents a facile strategy to enhance CO2 distribution and optimize triple-phase boundary formation by manipulating the surface wettability of HFGDEs. The infiltration and melting of hydrophobic agents (e.g., polytetrafluoroethylene (PTFE)) have been carried out on the Zn nanosheet-deposited Cu hollow fiber. The fluorescent residue area (water surface coverage) with a similar to 66.7 % decrease and the observation of CO2 bubbling enhancement confirmed the improvement of CO2 distribution on HFGDE, and the resulting HFGDE achieved around similar to 39 % increase in terms of industrial-scale CO partial current density and 4 times higher stability compared to the pristine HFGDE. This research highlights the use of HFGDEs to achieve gas flow-through, further combining with a versatile strategy to enhance CO2 distribution which can be applied for other gas-phase electrolysis reactions through creating improved triple-phase interfaces and maximizing reaction activity.

Separators are essential for safe and efficient battery operation. Polyolefin separators like polyethylene (PE) are widely used in lithium-ion batteries but are incompatible with strongly polar electrolytes, such as chloroaluminate ionic liquids in rechargeable aluminum batteries (RABs). Glass fiber (GF) membranes are commonly used in RABs due to good wettability, but their excessive thickness, mechanical fragility, and nonuniform macropores limit practicality. This study investigates the feasibility of utilizing an alumina-coated PE (Al2O3-PE) separator for RABs. Theoretical and experimental analyses show that the polarizable Al2O3 induces strong ion-dipole interactions with RAB electrolytes, imparting exceptional wettability and electrolyte uptake. Combined with its uniform nanopore structure, Al2O3-PE enables homogeneous ion flux for reversible Al stripping/plating with dendrite suppression. In RABs with graphene cathodes, Al2O3-PE outperforms GF separators, achieving higher capacity, improved rate performance, and long cycling stability. Flexible pouch cells with Al2O3-PE demonstrate stable operation under bending, supporting practical application.

Piezoelectric materials convert mechanical energy into electrical energy and are used as sensors, actuators, and energy harvesters in Industry 4.0. Polymer nanocomposites with adjustable performance and affordability could transform piezoelectric technology. Fluoropolymers like poly(vinylidene fluoride) (PVDF) and its copolymers are common in developing these composites with various nanoparticles. Zinc oxide (ZnO) is promising due to its non-centrosymmetric structure, high piezoelectric coefficient, and versatile nanostructure synthesis. This review covers recent trends in fabricating and optimizing piezoelectric polymer nanocomposites based on fluoropolymers and ZnO, including synthesis principles and advanced methods. It examines approaches to enhance piezoelectric and physical properties, emphasizing PVDF/ZnO composites' applications. The review also discusses challenges and future directions, serving as a resource for researchers and industry professionals aiming to improve piezoelectric materials for next-generation use.

Despite being a compelling alternative to the existing lithium‐ion battery technology, the unavailability of cathodes with high energy density and capacity poses a key challenge toward the wider adaption of sodium‐ion batteries (NIB). In this regard, iron‐rich NASICONs have triggered significant attention owing to a greater abundance of Fe and higher operating voltages of Fe 2+ /Fe 3+ redox‐couple. A major roadblock in such cathodes stems from the voltage hysteresis at higher current rates. Herein, a NASICON‐type NaFe 2‐x In x (PO 4 )(MoO 4 ) 2 (NFIPM) cathode is reported that shows a stable single‐phase solid‐solution reaction with significantly attenuated overpotential. Indium is strategically incorporated at the iron sites, expanding the lattice space to facilitate enhanced sodium‐ion diffusion and also reducing the energy bandgap of NFIPM. Magnetic susceptibility (M‐T) and Electron Paramagnetic Resonance (EPR) measurements reveal an increased spin state of iron following indium substitution. First principle calculations also confirm the lowering of the Na + migration energy barrier post indium doping. The optimized NFIPM10 shows a specific capacity of 111.85 mAh g −1 at 0.1 C with remarkable cycling stability of up to 800 cycles at 2C. In situ X‐ray diffraction confirms reversible structural stability of NFIPM during (de)sodiation, emphasizing the role of strategic doping in enhancing sodium‐ion storage.

In this contribution, the development of a self‐healable GaSb alloy featuring a confined Sn (core‐shell) structure is reported for stable Na + storage in an ether‐based electrolyte. The core‐shell architecture of GaSb@Sn has been validated through high‐angle annular dark field‐scanning transmission electron microscopy (HAADF‐STEM) paired with electron energy loss spectroscopy (EELS) analysis. The GaSb@Sn support on carbon electrode has delivered specific capacity of 560 mAh g electrode −1 at 50 mA g −1 with 89% retention capacity after 1200 cycles and specific capacity of 449 mAh g electrode −1 at 2 Ag −1 with 82% retention capacity after 2000 cycles. The GaSb@Sn/C electrode stores Na + by forming Na‐Sn, Na‐Sb‐O, and Na‐Ga‐O intermetallic compounds, as confirmed by operando XRD studies. Operando electrochemical dilatometry studies reveal that the self‐healable electrode expands by 33% at the electrode level during Na + insertion, significantly lower than the theoretically predicted expansion of Sn, which is 420%. DFT calculations show that the adsorption of diglyme on GaSb@Sn (−0.4 eV) is weaker than that on bulk Sn (−5.1 eV). The weaker interaction between diglyme and GaSb@Sn could be responsible for the thinner SEI formation on the edges of GaSb@Sn, thereby resulting in the high initial coulombic efficiency (GaSb@Sn‐ 81%, Bulk Sn‐62%) and stable cycle life.

Lithium-ion batteries are commonly used for energy storage due to their long lifespan and high energy density, but the use of unsafe electrolytes poses significant health and safety concerns. An alternative source is necessary to maintain electrochemical efficacy. This research demonstrates new safe glyme-based electrolytes for silica/carbon (SiOx/C) nanocomposite derived from Australian rice husk (RH). The quality of SiOx/C was preserved by using deep eutectic solvent-based pre-treatment and single-step carbonization, which was confirmed through the X-ray analysis of the crystalline phase of silica. The electrochemical assessment of SiOx/C anode using various glyme-based electrolytes for LIBs was carried out. Among them, the resultant half cells based on diglyme electrolyte is superior to others with the first discharge capacity at 1274 mAh/g and a reversible discharge capacity of 759.7 mAh/g. Ex-situ SEM and Time-of-Flight Secondary Ion Mass Spectrometry (ToF- SIMS) analysis of the electrode indicated that diglyme not only improves the capacity but also sustains the electrode architecture for longer cycle life with more LiF-based components and also showed the absence of HF components. Importantly, the addition of fluoroethylene carbonate (FEC) additive enhanced the cycling stability. These results provide a new perspective on developing advanced SiOx/C anode using glyme electrolytes for Li-ion batteries.