Selective CO2 Photoreduction into CH4 Triggered by the Synergy between Oxygen Vacancy and Ru Substitution under Near-Infrared Light Irradiation.

Near-infrared (NIR) light powdered CO2 photoreduction reaction is generally restricted to the separation efficiency of photogenerated carriers and the supply of active hydrogen (*H). Herein, the study reports a retrofitting hydrogenated MoO3-x (H-MoO3-x) nanosheet photocatalysts with Ru single atom substitution (Ru@H-MoO3-x) fabricated by one-step solvothermal method. Experiments together with theoretical calculations demonstrate that the synergistic effect of Ru substitution and oxygen vacancy can not only inhibit the recombination of photogenerated carriers, but also facilitate the CO2 adsorption/activation as well as the supply of *H. Compared with H-MoO3-x, the Ru@H-MoO3-x exhibit more favorable formation of *CHO in the process of *CO conversion due to the fast *H generation on electron-rich Ru sites and transfer to *CO intermediates, leading to the preferential photoreduction of CO2 to CH4 with high selectivity. The optimized Ru@H-MoO3-x exhibits a superior CO2 photoreduction activity with CH4 evolution rate of 111.6 and 39.0 µmol gcatalyst -1 under full spectrum and NIR light irradiation, respectively, which is 8.8 and 15.0 times much higher than that of H-MoO3-x. This work provides an in-depth understanding at the atomic level on the design of NIR responsive photocatalyst for achieving the goal of carbon neutrality.

A bio-based functional separator enables dendrite-free anodes in aqueous zinc-ion batteries.

Aqueous zinc-ion batteries (AZIBs) have garnered considerable interest as potential solutions for large-scale energy storage systems, owing to their cost-effectiveness and high safety. Nonetheless, the development of AZIBs is hindered by significant challenges associated with dendrite growth and side reactions on Zn anodes. Here, a bio-based separator derived from cellulose was developed for the dendrite-free anode in AZIBs. In addition, the separator is notable for its ultra-low cost and biodegradability in contrast to the commonly used commercial glass fiber (GF) separators. The mechanical strength of the separator is enhanced by the cross-linking of hydrogen bonds, effectively inhibiting dendrite growth. The zinc-philic groups facilitate better binding to Zn2+, resulting in uniform nucleation and deposition. The hydrophilic groups aid in trapping water molecules, thereby preventing side reactions of the electrolyte. The Zn||Zn symmetric cell with this separator can sustain a long cycle life for over 800 h, indicating stable Zn2 + plating and stripping with suppressed dendrite growth. Concurrently, the assembled Zn||VO2 full batteries exhibited a capacity retention rate of 61.87% after 1,000 cycles at 1 A g-1 with an initial capacity of 140 mAh g-1. This work highlights a stable, economical, and eco-friendly approach to the design of bio-based separators in AZIBs for sustainable energy storage systems.

Regulation of Interface Ion Transport by Electron Ionic Conductor Construction toward High-Voltage and High-Rate LiNi0.5Co0.2Mn0.3O2 Cathodes in Lithium Ion Battery.

Simultaneously achieving high-energy-density and high-power-density is a crucial yet challenging objective in the pursuit of commercialized power batteries. In this study, atomic layer deposition (ALD) is employed combined with a coordinated thermal treatment strategy to construct a densely packed, electron-ion dual conductor (EIC) protective coating on the surface of commercial LiNi0.5Co0.2Mn0.3O2 (NCM523) cathode material, further enhanced by gradient Al doping (Al@EIC-NCM523). The ultra-thin EIC effectively suppresses side reactions, thereby enhancing the stability of the cathode-electrolyte interphase (CEI) at high-voltages. The EIC's dual conduction capability provides a potent driving force for Li+ transport at the interface, promoting the formation of rapid ion deintercalation pathways within the Al@EIC-NCM523 bulk phase. Moreover, the strategic gradient doping of Al serves to anchor the atomic spacing of Ni and O within the structure of Al@EIC-NCM523, curbing irreversible phase transitions at high-voltages and preserving the integrity of its layered structure. Remarkably, Al@EIC-NCM523 displays an unprecedented rate capability (114.7 mAh g-1 at 20 C), and a sustained cycling performance (capacity retention of 74.72% after 800 cycles at 10 C) at 4.6 V. These findings demonstrate that the proposed EIC and doping strategy holds a significant promise for developing high-energy-density and high-power-density lithium-ion batteries (LIBs).

Covalent Organic Framework-Based Materials for Advanced Lithium Metal Batteries.

Lithium metal batteries (LMBs), with high energy densities, are strong contenders for the next generation of energy storage systems. Nevertheless, the unregulated growth of lithium dendrites and the unstable solid electrolyte interphase (SEI) significantly hamper their cycling efficiency and raise serious safety concerns, rendering LMBs unfeasible for real-world implementation. Covalent organic frameworks (COFs) and their derivatives have emerged as multifunctional materials with significant potential for addressing the inherent problems of the anode electrode of the lithium metal. This potential stems from their abundant metal-affine functional groups, internal channels, and widely tunable architecture. The original COFs, their derivatives, and COF-based composites can effectively guide the uniform deposition of lithium ions by enhancing conductivity, transport efficiency, and mechanical strength, thereby mitigating the issue of lithium dendrite growth. This review provides a comprehensive analysis of COF-based and derived materials employed for mitigating the challenges posed by lithium dendrites in LMB. Additionally, we present prospects and recommendations for the design and engineering of materials and architectures that can render LMBs feasible for practical applications.

Superior sodiophilicity and molecule crowding of crown ether boost the electrochemical performance of all-climate sodium-ion batteries.

Sodium-ion batteries (SIBs) as one of the promising alternatives to lithium-ion batteries have achieved remarkable progress in the past. However, the all-climate performance is still very challenging for SIBs. Herein, 15-Crown-5 (15-C-5) is screened as an electrolyte additive from a number of ether molecules theoretically. The good sodiophilicity, high molecule rigidity, and bulky size enable it to reshape the solvation sheath and promote the anion engagement in the solvated structures by molecule crowding. This change also enhances Na-ion transfer, inhibits side reactions, and leads to a thin and robust solid-electrolyte interphase. Furthermore, the electrochemical stability and operating temperature windows of the electrolyte are extended. These profits improve the electrochemical performance of SIBs in all climates, much better than the case without 15-C-5. This improvement is also adopted to µ-Sn, µ-Bi, hard carbon, and MoS2. This work opens a door to prioritize the potential molecules in theory for advanced electrolytes.

Interfacial Spinel Local Interlocking Strategy Toward Structural Integrity in P3 Oxide Cathodes.

P3-layered transition oxide cathodes have garnered considerable attention owing to their high initial capacity, rapid Na+ kinetics, and less energy consumption during the synthesis process. Despite these merits, their practical application is hindered by the substantial capacity degradation resulting from unfavorable structural transformations, Mn dissolution and migration. In this study, we systematically investigated the failure mechanisms of P3 cathodes, encompassing Mn dissolution, migration, and the irreversible P3-O3' phase transition, culminating in severe structural collapse. To address these challenges, we proposed an interfacial spinel local interlocking strategy utilizing P3/spinel intergrowth oxide as a proof-of-concept material. As a result, P3/spinel intergrowth oxide cathodes demonstrated enhanced cycling performance. The effectiveness of suppressing Mn migration and maintaining local structure of interfacial spinel local interlocking strategy was validated through depth-etching X-ray photoelectron spectroscopy, X-ray absorption spectroscopy, and in situ synchrotron-based X-ray diffraction. This interfacial spinel local interlocking engineering strategy presents a promising avenue for the development of advanced cathode materials for sodium-ion batteries.

Molten-Salt Electrochemical-Assisted Synthesis of the CeO2-OV@GC Composite-Supported Pt Clusters with a Pt-O-Ce Structure for the Oxygen Reduction Reaction.

Highly active and robust Pt-based electrocatalysts for an oxygen reduction reaction (ORR) are of crucial significance for the development of proton exchange membrane fuel cells (PEMFCs). Herein, the high-loading and well-dispersive Pt clusters on graphitic carbon-supported CeO2 with abundant oxygen vacancies (PtAC/CeO2-OV@GC) were successfully fabricated by a molten-salt electrochemical-assisted method. The bonding of Pt with the highly electronegative O induces charge redistribution through the Pt-O-Ce structure, thus reducing the adsorption energies of oxygen-containing species. Such a PtAC/CeO2-OV@GC electrocatalyst exhibits a greatly enhanced ORR performance with a mass activity of 0.41 ± 0.02 A·mg-1Pt at 0.9 V versus a reversible hydrogen electrode, which is 2.7 times the value of a commercial Pt/C catalyst and shows negligible activity decay after 20000 cycles of accelerated degradation tests. It is anticipated that this work will provide enlightening guidance on the controllable synthesis and rational design of high-performance Pt-based electrocatalysts for PEMFCs.

Scalable Precise Nanofilm Coating and Gradient Al Doping Enable Stable Battery Cycling of LiCoO2 at 4.7†V.

The quest for smart electronics with higher energy densities has intensified the development of high-voltage LiCoO2 (LCO). Despite their potential, LCO materials operating at 4.7 V faces critical challenges, including interface degradation and structural collapse. Herein, we propose a collective surface architecture through precise nanofilm coating and doping that combines an ultra-thin LiAlO2 coating layer and gradient doping of Al. This architecture not only mitigates side reactions, but also improves the Li+ migration kinetics on the LCO surface. Meanwhile, gradient doping of Al inhibited the severe lattice distortion caused by the irreversible phase transition of O3-H1-3-O1, thereby enhanced the electrochemical stability of LCO during 4.7 V cycling. DFT calculations further revealed that our approach significantly boosts the electronic conductivity. As a result, the modified LCO exhibited an outstanding reversible capacity of 230 mAh g-1 at 4.7 V, which is approximately 28 % higher than the conventional capacity at 4.5 V. To demonstrate their practical application, our cathode structure shows improved stability in full pouch cell configuration under high operating voltage. LCO exhibited an excellent cycling stability, retaining 82.33 % after 1000 cycles at 4.5 V. This multifunctional surface modification strategy offers a viable pathway for the practical application of LCO materials, setting a new standard for the development of high-energy-density and long-lasting electrode materials.

Electric Double Layer Regulator Design through a Functional Group Assembly Strategy towards Long-Lasting Zinc Metal Batteries.

Regulating the electric double layer (EDL) structure of the zinc metal anode by using electrolyte additives is an efficient way to suppress interface side reactions and facilitate uniform zinc deposition. Nevertheless, there are no reports investigating the proactive design of EDL-regulating additives before the start of experiments. Herein, a functional group assembly strategy is proposed to design electrolyte additives for modulating the EDL, thereby realizing a long-lasting zinc metal anode. Specifically, by screening ten common functional groups, N, N-dimethyl-1H-imidazole-1-sulfonamide (IS) is designed by assembling an imidazole group, characterized by its high adsorption capability on the zinc anode, and a sulfone group, which exhibits strong binding with Zn2+ ions. Benefiting from the adsorption functionalization of the imidazole group, the IS molecules occupy the position of H2O in the inner Helmholtz layer of the EDL, forming a molecular protective layer to inhibit H2O-induced side reactions. Meanwhile, the sulfone group in IS, acting as a binding site to Zn2+, promotes the de-solvation of Zn2+ ions, facilitating compact zinc deposition. Consequently, the utilization of IS significantly extending the cycling stability of Zn||Zn and Zn||NaV3O8 ⋅ 1.5H2O full cell. This study offers an innovative approach to the design of EDL regulators for high-performance zinc metal batteries.

Understanding the charge transfer effects of single atoms for boosting the performance of Na-S batteries.

The effective flow of electrons through bulk electrodes is crucial for achieving high-performance batteries, although the poor conductivity of homocyclic sulfur molecules results in high barriers against the passage of electrons through electrode structures. This phenomenon causes incomplete reactions and the formation of metastable products. To enhance the performance of the electrode, it is important to place substitutable electrification units to accelerate the cleavage of sulfur molecules and increase the selectivity of stable products during charging and discharging. Herein, we develop a single-atom-charging strategy to address the electron transport issues in bulk sulfur electrodes. The establishment of the synergistic interaction between the adsorption model and electronic transfer helps us achieve a high level of selectivity towards the desirable short-chain sodium polysulfides during the practical battery test. These finding indicates that the atomic manganese sites have an enhanced ability to capture and donate electrons. Additionally, the charge transfer process facilitates the rearrangement of sodium ions, thereby accelerating the kinetics of the sodium ions through the electrostatic force. These combined effects improve pathway selectivity and conversion to stable products during the redox process, leading to superior electrochemical performance for room temperature sodium-sulfur batteries.

Advancements in aqueous zinc-iodine batteries: a review.

Aqueous zinc-iodine batteries stand out as highly promising energy storage systems owing to the abundance of resources and non-combustible nature of water coupled with their high theoretical capacity. Nevertheless, the development of aqueous zinc-iodine batteries has been impeded by persistent challenges associated with iodine cathodes and Zn anodes. Key obstacles include the shuttle effect of polyiodine and the sluggish kinetics of cathodes, dendrite formation, the hydrogen evolution reaction (HER), and the corrosion and passivation of anodes. Numerous strategies aimed at addressing these issues have been developed, including compositing with carbon materials, using additives, and surface modification. This review provides a recent update on various strategies and perspectives for the development of aqueous zinc-iodine batteries, with a particular emphasis on the regulation of I2 cathodes and Zn anodes, electrolyte formulation, and separator modification. Expanding upon current achievements, future initiatives for the development of aqueous zinc-iodine batteries are proposed, with the aim of advancing their commercial viability.

Routes to high-performance layered oxide cathodes for sodium-ion batteries.

Sodium-ion batteries (SIBs) are experiencing a large-scale renaissance to supplement or replace expensive lithium-ion batteries (LIBs) and low energy density lead-acid batteries in electrical energy storage systems and other applications. In this case, layered oxide materials have become one of the most popular cathode candidates for SIBs because of their low cost and comparatively facile synthesis method. However, the intrinsic shortcomings of layered oxide cathodes, which severely limit their commercialization process, urgently need to be addressed. In this review, inherent challenges associated with layered oxide cathodes for SIBs, such as their irreversible multiphase transition, poor air stability, and low energy density, are systematically summarized and discussed, together with strategies to overcome these dilemmas through bulk phase modulation, surface/interface modification, functional structure manipulation, and cationic and anionic redox optimization. Emphasis is placed on investigating variations in the chemical composition and structural configuration of layered oxide cathodes and how they affect the electrochemical behavior of the cathodes to illustrate how these issues can be addressed. The summary of failure mechanisms and corresponding modification strategies of layered oxide cathodes presented herein provides a valuable reference for scientific and practical issues related to the development of SIBs.

A Critical Review on Room-Temperature Sodium-Sulfur Batteries: From Research Advances to Practical Perspectives.

Room-temperature sodium-sulfur (RT-Na/S) batteries are promising alternatives for next-generation energy storage systems with high energy density and high power density. However, some notorious issues are hampering the practical application of RT-Na/S batteries. Besides, the working mechanism of RT-Na/S batteries under practical conditions such as high sulfur loading, lean electrolyte, and low capacity ratio between the negative and positive electrode (N/P ratio), is of essential importance for practical applications, yet the significance of these parameters has long been disregarded. Herein, it is comprehensively reviewed recent advances on Na metal anode, S cathode, electrolyte, and separator engineering for RT-Na/S batteries. The discrepancies between laboratory research and practical conditions are elaborately discussed, endeavors toward practical applications are highlighted, and suggestions for the practical values of the crucial parameters are rationally proposed. Furthermore, an empirical equation to estimate the actual energy density of RT-Na/S pouch cells under practical conditions is rationally proposed for the first time, making it possible to evaluate the gravimetric energy density of the cells under practical conditions. This review aims to reemphasize the vital importance of the crucial parameters for RT-Na/S batteries to bridge the gaps between laboratory research and practical applications.

Establishing Pinhole Deposition Mode of Zn via Scalable Monolayer Graphene Film.

The uneven texture evolution of Zn during electrodeposition would adversely impact upon the lifespan of aqueous Zn metal batteries. To address this issue, tremendous endeavors are made to induce Zn(002) orientational deposition employing graphene and its derivatives. Nevertheless, the effect of prototype graphene film over Zn deposition behavior has garnered less attention. Here, it is attempted to solve such a puzzle via utilizing transferred high-quality graphene film with controllable layer numbers in a scalable manner on a Zn foil. The multilayer graphene fails to facilitate a Zn epitaxial deposition, whereas the monolayer film with slight breakages steers a unique pinhole deposition mode. In-depth electrochemical measurements and theoretical simulations discover that the transferred graphene film not only acts as an armor to inhibit side reactions but also serves as a buffer layer to homogenize initial Zn nucleation and decrease Zn migration barrier, accordingly enabling a smooth deposition layer with closely stacked polycrystalline domains. As a result, both assembled symmetric and full cells manage to deliver satisfactory electrochemical performances. This study proposes a concept of "pinhole deposition" to dictate Zn electrodeposition and broadens the horizons of graphene-modified Zn anodes.

Linearly Interlinked Fe-Nx-Fe Single Atoms Catalyze High-Rate Sodium-Sulfur Batteries.

Linearly interlinked single atoms offer unprecedented physiochemical properties, but their synthesis for practical applications still poses significant challenges. Herein, linearly interlinked iron single-atom catalysts that are loaded onto interconnected carbon channels as cathodic sulfur hosts for room-temperature sodium-sulfur batteries are presented. The interlinked iron single-atom exhibits unique metallic iron bonds that facilitate the transfer of electrons to the sulfur cathode, thereby accelerating the reaction kinetics. Additionally, the columnated and interlinked carbon channels ensure rapid Na+ diffusion kinetics to support high-rate battery reactions. By combining the iron atomic chains and the topological carbon channels, the resulting sulfur cathodes demonstrate effective high-rate conversion performance while maintaining excellent stability. Remarkably, even after 5000 cycles at a current density of 10 A g-1, the Na-S battery retains a capacity of 325 mAh g-1. This work can open a new avenue in the design of catalysts and carbon ionic channels, paving the way to achieve sustainable and high-performance energy devices.

Formulating Local Environment of Oxygen Mitigates Voltage Hysteresis in Li-Rich Materials.

Li-rich cathode materials have emerged as one of the most prospective options for Li-ion batteries owing to their remarkable energy density (>900 Wh kg-1). However, voltage hysteresis during charge and discharge process lowers the energy conversion efficiency, which hinders their application in practical devices. Herein, the fundamental reason for voltage hysteresis through investigating the O redox behavior under different (de)lithiation states is unveiled and it is successfully addressed by formulating the local environment of O2-. In Li-rich Mn-based materials, it is confirmed that there exists reaction activity of oxygen ions at low discharge voltage (<3.6 V) in the presence of TM-TM-Li ordered arrangement, generating massive amount of voltage hysteresis and resulting in a decreased energy efficiency (80.95%). Moreover, in the case where Li 2b sites are numerously occupied by TM ions, the local environment of O2- evolves, the reactivity of oxygen ions at low voltage is significantly inhibited, thus giving rise to the large energy conversion efficiency (89.07%). This study reveals the structure-activity relationship between the local environment around O2- and voltage hysteresis, which provides guidance in designing next-generation high-performance cathode materials.

Sequential co-reduction of nitrate and carbon dioxide enables selective urea electrosynthesis.

Despite the recent achievements in urea electrosynthesis from co-reduction of nitrogen wastes (such as NO3-) and CO2, the product selectivity remains fairly mediocre due to the competing nature of the two parallel reduction reactions. Here we report a catalyst design that affords high selectivity to urea by sequentially reducing NO3- and CO2 at a dynamic catalytic centre, which not only alleviates the competition issue but also facilitates C-N coupling. We exemplify this strategy on a nitrogen-doped carbon catalyst, where a spontaneous switch between NO3- and CO2 reduction paths is enabled by reversible hydrogenation on the nitrogen functional groups. A high urea yield rate of 596.1 µg mg-1 h-1 with a promising Faradaic efficiency of 62% is obtained. These findings, rationalized by in situ spectroscopic techniques and theoretical calculations, are rooted in the proton-involved dynamic catalyst evolution that mitigates overwhelming reduction of reactants and thereby minimizes the formation of side products.

Nickel Nanoparticles Protruding from Molybdenum Carbide Micropillars with Carbon Layer-Protected Biphasic 0D/1D Heterostructures for Efficient Water Splitting.

It remains a tremendous challenge to achieve high-efficiency bifunctional electrocatalysts for both the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER) for hydrogen production by water splitting. Herein, a novel hybrid of 0D nickel nanoparticles dispersed on the one-dimensional (1D) molybdenum carbide micropillars embedded in the carbon layers (Ni/Mo2C@C) was successfully prepared on nickel foam by a facile pyrolysis strategy. During the synthesis process, the nickel nanoparticles and molybdenum carbide were simultaneously generated under H2 and C2H2 mixed atmospheres and conformally encapsulated in the carbon layers. Benefiting from the distinctive 0D/1D heterostructure and the synergistic effect of the biphasic Mo2C and Ni together with the protective effect of the carbon layer, the reduced activation energy barriers and fast catalytic reaction kinetics can be achieved, resulting in a small overpotential of 96 mV for the HER and 266 mV for the OER at the current density of 10 mA cm-2 together with excellent durability in 1.0 M KOH electrolyte. In addition, using the developed Ni/Mo2C@C as both the cathode and anode, the constructed electrolyzer exhibits a small voltage of 1.55 V for the overall water splitting. The novel designed Ni/Mo2C@C may give inspiration for the development of efficient bifunctional catalysts with low-cost transition metal elements for water splitting.

Mo-doping heterojunction: interfacial engineering in an efficient electrocatalyst for superior simulated seawater hydrogen evolution.

Exploring economical, efficient, and stable electrocatalysts for the seawater hydrogen evolution reaction (HER) is highly desirable but is challenging. In this study, a Mo cation doped Ni0.85Se/MoSe2 heterostructural electrocatalyst, Mox-Ni0.85Se/MoSe2, was successfully prepared by simultaneously doping Mo cations into the Ni0.85Se lattice (Mox-Ni0.85Se) and growing atomic MoSe2 nanosheets epitaxially at the edge of the Mox-Ni0.85Se. Such an Mox-Ni0.85Se/MoSe2 catalyst requires only 110 mV to drive current densities of 10 mA cm-2 in alkaline simulated seawater, and shows almost no obvious degradation after 80 h at 20 mA cm-2. The experimental results, combined with the density functional theory calculations, reveal that the Mox-Ni0.85Se/MoSe2 heterostructure will generate an interfacial electric field to facilitate the electron transfer, thus reducing the water dissociation barrier. Significantly, the heteroatomic Mo-doping in the Ni0.85Se can regulate the local electronic configuration of the Mox-Ni0.85Se/MoSe2 heterostructure catalyst by altering the coordination environment and orbital hybridization, thereby weakening the bonding interaction between the Cl and Se/Mo. This synergistic effect for the Mox-Ni0.85Se/MoSe2 heterostructure will simultaneously enhance the catalytic activity and durability, without poisoning or corrosion of the chloride ions.

A Holistic Additive Protocol Steers Dendrite-Free Zn(101) Orientational Electrodeposition.

Orientation guidance has shown its cutting edges in electrodeposition modulation to promote Zn anode stability toward commercialized standards. Nevertheless, large-scale orientational deposition is handicapped by the competition between Zn-ion reduction and mass transfer. Herein, a holistic electrolyte additive protocol is put forward via incorporating bio-derived dextrin molecules into a zinc sulfate electrolyte bath. Electrochemical tests in combination with molecular dynamics simulations demonstrate the alleviation of concentration polarization throughout accelerating Zn2+ diffusion and retarding their reduction. The predominant (101) texture on inert current collectors (i.e., Cu, Ti, and stainless steel) and (101)/(002) textures on Zn foils afford homogeneous electrical field distribution, which is contributed by the work difference to form the 2D nucleus and the adsorption of dextrin molecules, respectively. Consequently, the symmetric cell harvests a longevous cycling lifespan of over 4000 h at 0.5 mA cm-2 /0.5 mAh cm-2 while the Zn@Cu electrode sustains for 240 h at a high depth of discharge of 40%.