The practical implementation of an anode-free lithium-metal battery with promising high capacity is hampered by dendrite formation and low coulombic efficiency. Most notably, these challenges stem from non-uniform lithium plating and unstable SEI layer formation on the bare copper electrode. Herein, we revealed the homogeneous deposition of lithium and effective suppression of dendrite formation using a copper electrode coated with a polyethylene oxide (PEO) film in an electrolyte comprising 1 M LiTFSI, DME/DOL (1/1, v/v) and 2 wt% LiNO₃. More importantly, the PEO film coating promoted the formation of a thin and robust SEI layer film by hosting lithium and regulating the inevitable reaction of lithium with the electrolyte. The modified electrode exhibited stable cycling of lithium with an average coulombic efficiency of ∼100% over 200 cycles and low voltage hysteresis (∼30 mV) at a current density of 0.5 mA cm⁻². Moreover, we tested the anode-free battery experimentally by integrating it with an LiFePO₄ cathode into a full-cell configuration (Cu@PEO/LiFePO₄). The new cell demonstrated stable cycling with an average coulombic efficiency of 98.6% and capacity retention of 30% in the 200^th cycle at a rate of 0.2C. These impressive enhancements in cycle life and capacity retention result from the synergy of the PEO film coating, high electrode–electrolyte interface compatibility, stable polar oligomer formation from the reduction of 1,3-dioxolane and the generation of SEI-stabilizing nitrite and nitride upon lithium nitrate reduction. Our result opens up a new route to realize anode-free batteries by modifying the copper anode with PEO to achieve ever more demanding yet safe interfacial chemistry and control of dendrite formation.

The will to circumvent capacity fading, Li dendrite formation, and low coulombic efficiency in anode-free Li-metal batteries (AFLMBs) requires a radical change in the science underpinning new materials discovery, battery design, and understanding electrode interfaces. Herein, a Cu current collector formed with ultrathin multilayer graphene grown via chemical vapor deposition (CVD) was used as an artificial layer to stabilize the electrode interface and sandwich-deposited Li with Cu. A multilayer graphene film's superior strength, chemical stability, and flexibility make it an excellent choice to modify a Cu electrode. Fabricating an anode bigger than the cathode improved the alignment of the electrodes during assembly, minimizing interfacial stress. Here, 19 mm electrodes when paired with a commercial LiFePO₄ cathode (mass loading: ∼12 mg cm⁻²) delivered the first-cycle discharge capacities of 147 and 151 mA h g⁻¹ for bare and multilayer-graphene-protected electrodes, respectively, which could alleviate the big hurdle (initial capacity loss) in anode-free batteries. After 100 round-trip cycles, bare Cu and multilayer-graphene-protected electrodes retained ∼46 and ∼61% of their initial capacities, respectively, in an ether-based electrolyte at the rate of 0.1 C.

Metal–air batteries, such as zinc–air, are known for their high specific capacity and environmental friendliness. Operational longevity and energy efficiency, however, remain constrained by sluggish reaction kinetics, elevated overpotential, and interfacial instability during charge–discharge cycles. While noble metal catalysts have historically addressed these gaps, strategic resource allocation now prioritizes abundant, commercially reachable, and cost‐effective alternatives. Biomass, a sustainable resource, is crucial in the development of metal‐free heteroatom‐doped biomass carbon nanostructured electrocatalysts and porous air electrodes with excellent performance for such batteries. These novel materials emerge as critical enablers, leveraging inherent heteroatom density, tunable pore architectures, and the potential for transition metal doping and codoping to optimize bifunctional activity. They have also been identified as prospective alternatives for the next generation of bifunctional electrocatalysts for oxygen reduction and evolution reactions. This review provides a comprehensive overview of the potential of metal‐free heteroatom‐doped biomass carbon nanostructured electrocatalysts for the forthcoming generations of oxygen reduction and evolution processes, as well as bifunctional electrocatalysts and porous electrodes for zinc–air rechargeable batteries. The physicochemical features of these batteries, stabilization techniques for zinc electrodes, reaction processes, and the dynamic evolution of the electrolyte–electrode interface have also been conferred.

The urgent global need for efficient, clean, and sustainable energy storage technologies has underscored the importance of supercapacitors as vital components in future energy systems. Their high power density, excellent cycle life, and rapid charge-discharge capabilities make them particularly attractive for diverse sustainable applications. Among emerging materials, biomass-derived carbon has gained significant attention due to its renewability, hierarchical porosity, and tunable surface chemistry, especially when enhanced through heteroatom modification. These distinctive features improve electrochemical performance, positioning biocarbons as promising candidates for next-generation supercapacitor electrodes. This review highlights recent advances (2020-2025) in biocarbon-based supercapacitors, focusing on how structural engineering, porous architectures, and chemical doping influence charge retention, energy density, and conductivity. Beyond performance metrics, it emphasizes the environmental and circular-economy benefits of recycling biowastes for sustainable energy solutions. The paper concludes with reflections on current challenges, practical considerations for scaling, and future research directions to advance biomass-derived carbon electrodes.

Rechargeable zinc-air batteries (RZABs) are vital for advancing sustainable energy storage technologies. Renewable single-metal-doped nanostructured carbon from biomass offers promising electrocatalysts and electrodes, enabling efficient oxygen reactions for sustainable battery technologies. This review exemplifies the prospective possibility of using carbonized biomass in the advancement of sustainable energy storage, thereby initiating an avenue toward higher efficiency and environmentally friendly RZABs. This review examines various synthetic charring methods, structural features of single-metal-doped materials compared with traditional catalysts, and their electrochemical performance toward secondary zinc-air batteries’ efficiency, stability, cyclability, and durability, as well as general performance, which is directly related to their cost. Finally, it discusses the research gaps and future directions, underlining the research that needs to optimize the synthesis methods and to reveal in detail the structure-activity relationships of biomass carbons toward the proposed electrocatalytic applications.

Graphene-based materials (GBMs) are a prospective material of choice for rechargeable battery electrodes because of their unique set of qualities, which include tunable interlayer channels, high specific surface area, and strong electrical conductivity characteristics. The market for commercial rechargeable batteries is now dominated by lithium-ion batteries (LIBs). One of the primary factors impeding the development of new energy vehicles and large-scale energy storage applications is the safety of LIBs. Zinc-based rechargeable batteries have emerged as a viable substitute for rechargeable batteries due to their affordability, safety, and improved performance. This review article explores recent developments in the synthesis and advancement of GBMs for rechargeable zinc–air batteries (ZABs) and common graphene-based electrocatalyst types. An outlook on the difficulties and probable future paths of this extremely promising field of study is provided at the end.