Wide Potential Window Research Articles

Guanine-derived carbon nanosheet encapsulated Ni nanoparticles for efficient CO2 electroreduction.

Developing novel electrocatalysts for achieving high selectivity and faradaic efficiency in the carbon dioxide reduction reaction (CO2RR) poses a major challenge. In this study, a catalyst featuring a nitrogen-doped carbon shell-coated Ni nanoparticle structure is designed for efficient carbon dioxide (CO2) electroreduction to carbon monoxide (CO). The optimal Ni@NC-1000 catalyst exhibits remarkable CO faradaic efficiency (FECO) values exceeding 90% across a broad potential range of -0.55 to -0.9 V (vs. RHE), and attains the maximum FECO of 95.6% at -0.75 V (vs. RHE) in 0.5 M NaHCO3. This catalyst exhibits sustained carbon dioxide electroreduction activity with negligible decay after continuous electrolysis for 20 h. More encouragingly, a substantial current density of 200.3 mA cm-2 is achieved in a flow cell at -0.9 V (vs. RHE), reaching an industrial-level current density. In situ Fourier transform infrared spectroscopy and theoretical calculations demonstrate that its excellent catalytic performance is attributed to highly active pyrrolic nitrogen sites, promoting CO2 activation and significantly reducing the energy barrier for generating *COOH. To a considerable extent, this work presents an effective strategy for developing high-efficiency catalysts for electrochemical CO2 reduction across a wide potential window.

FeP-Fe3O4 nanospheres for electrocatalytic N2 reduction to NH3 under ambient conditions.

The electrocatalytic nitrogen reduction reaction (eNRR) under ambient conditions is deemed a promising alternative for NH3 synthesis. In this paper, an FeP-Fe3O4 nanocomposite electrocatalyst was prepared by phosphating annealing using Fe2O3 as a precursor, and the resulting FeP-Fe3O4 exhibited excellent N2-to-NH3-producing activity over a wide potential window. The highest faradaic efficiency of FeP-Fe3O4 is 11.02% at -0.1 V vs. reversible hydrogen electrode (RHE), and the maximum NH3 yield reaches 12.73 μg h-1 mgcat-1, comparable to or exceeding the reported values in this field. Furthermore, the FeP-Fe3O4 nanocomposite electrocatalyst presents high electrochemical stability, selectivity, and durability.

A Zn regulated Bi nanosheet catalyst for improving electrochemical CO2 reduction to formate over a wide potential window

The incorporation of the Zn element into Bi would optimize the adsorption of intermediates, facilitating the CO2RR to formate.

N/O coordinated s-block potassium atoms as highly active sites for electroreduction of CO2 to CO

The synthesized K–N, O/C catalyst demonstrates remarkable CO selectivity with over 90% Faraday efficiency (FE) in a wide potential window between −0.5 V and −0.9 V vs. RHE and the FE of CO is nearly unchanged during 24 h stability experiment.

Supercapacitance Performance of Mesoporous Mono- and Bi-Metallic Cobalt and Nickel Hydroxides Nanoflakes Chemically Deposited from Foam-Surfactant Liquid Crystal Dual Templates

Mesoporous 2D nanoflakes architectures of mono- and bi-metallic cobalt and nickel hydroxide (meso-Co-Ni(OH)2) hybrids were synthesized using novel chemical precipitation of foam-surfactant liquid crystal dual template (FSDT). The dissolved cobalt and nickel ions within the aqueous region of the Brij®78 surfactant template was reduced by the excess of sodium borohydride reducing agent that simultaneously generates excessive hydrogen foam as a double template. The physicochemical characterizations of the mono- and bi-metallic nanostructured Co-Ni(OH)2 hybrids performed using X-ray diffraction, surface area analyzer, scanning and transmission electrons microscopic techniques showed the formation of highly mesoporous hydroxides 2D nanoflakes architectures having an amorphous structure and surface area up to 253.50 m2/g. The electrochemical and supercapacitance evaluation of the mono-, and bi-metallic mesoporous hydroxides showed excellent Faradaic supercapacitance performance within a wider potential window and a higher charge and discharge rate. In particular the mesoporous monometallic of Co(OH)2, Ni(OH)2, bimetallic Co-Ni(OH)2 with Co/Ni ratios of (1:1), and (1:3), hydroxides showed total capacitances of 204, 869, 943, and 1384, F/g at charging current density of 5.0 A g−1 respectively and capacity retention rate of approximately 99.4% after 300 cycles. This suggests that these materials hold promise as electrode materials for energy storage applications.

Electrochemically triggered rational design of bismuth copper sulfide for wearable all-sulfide semi-solid-state supercapacitor with a wide operational potential window (1.8 V) and ultra-long life

Gel electrolyte-based wearable all-sulfide semi-solid-state supercapacitor (ASSSC) device with ∼100% capacitance retention across the 40 000 charge–discharge cycles. The ASSSC devices are attached to human fingers to power electronic gadgets.

Designing bifunctional perovskite catalysts for the oxygen reduction and evolution reactions.

The development of unified regenerative fuel cells (URFCs) necessitates an active and stable bifunctional oxygen electrocatalyst. The unique challenge of possessing high activity for both the oxygen reduction (ORR) and oxygen evolution (OER) reactions, while maintaining stability over a wide potential window impedes the design of bifunctional oxygen electrocatalysts. Herein, two design strategies are explored to optimize their performance. The first incorporates active sites for the ORR and OER, Mn and Co, into a single perovskite structure, which is achieved with the perovskites Ba0.5Sr0.5Co0.8Mn0.2O3-δ (BSCM) and La0.5Ba0.25Sr0.25Co0.5Mn0.5O3-δ (LBSCM). The second combines an active ORR perovskite catalyst (La0.4Sr0.6MnO3-δ (LSM)) with an OER active perovskite catalyst (Ba0.5Sr0.5Co0.8Fe0.2O3-δ (BSCF)) in a physical mixed composite (BSCF/LSM). The success of the two strategies is investigated by measuring the catalysts' catalytic performance and response to alternating reducing and oxidizing potentials to mimic the dynamic conditions experienced during the operation of URFCs. Additionally, the continuous, potentiodynamic change in Mn, Co, and Fe oxidation states during the ORR and OER is elucidated with operando X-ray absorption spectroscopy (XAS) measurements, revealing key insights into the nature of the active sites. The results reveal important catalyst physiochemical properties and provide a guide for future research and design principles for bifunctional oxygen electrocatalysts.

Impact of gate electrode on free chlorine sensing performance in solution-gated graphene field-effect transistors.

Free chlorine is widely used to disinfect water used for drinking and food processing. This requires highly sensitive, simple, and capable continuous-measurement sensors to enable the concentration of free chlorine in water to be monitored and controlled. Free chlorine sensors based on solution-gated graphene field-effect transistors (GFETs) are a suitable platform for highly sensitive and continuous measurements. However, their sensing mechanisms require further elucidation to improve their performance. In this study, we focused on the gate electrode and investigated its influence on the sensing performance. Using the free chlorine sensor based on the solution-gate GFET, we showed that the Dirac point voltage in the transfer curve changed significantly as the free chlorine concentration changed, and the electric double-layer capacitance of the gate electrode decreased. Furthermore, we demonstrated that a solution-gated GFET using graphene or boron-doped diamond as the gate electrode could be used to detect changes in the free chlorine concentration in the concentration range of tap water. The sensing performance in the low concentration range benefits from the wide potential window of carbon-based electrodes, which do not have electrochemically active sites. Using these carbon-based materials as gate electrodes, GFETs have the potential to be used as durable sensors that are resistant to surface fouling and oxidation.

Insight into the probability of ethoxy(pentafluoro)cyclotriphosphazene (PFPN) as the functional electrolyte additive in lithium-sulfur batteries.

Enhancing the flame retardancy of electrolytes and the stability of lithium anodes is of great significance to improve the safety performance of lithium-sulfur (Li-S) batteries. It is well known that the most commonly used ether based electrolyte solvents in Li-S batteries have a lower flash point and higher volatility than the ester electrolyte solvents in Li-ion batteries. Hence, lithium-sulfur batteries have greater safety risks than lithium-ion batteries. Herein, ethoxy(pentafluoro)cyclotriphosphazene (PFPN), which is commonly used as a flame retardant for ester electrolytes in lithium-ion batteries, is utilized as both a film-forming electrolyte additive and a flame retardant additive for the ether electrolyte to investigated its applicability in Li-S batteries. It is found that the ether electrolyte containing PFPN not only has good flame retardant properties and a wide potential window of about 5 V, but also can form a stable SEI film on the surface of a lithium anode. As a result, with the ether-based electrolyte containing 10 wt% PFPN, Li-Cu and Li-S batteries all delivered a stable cycling performance with a high coulombic Efficiency and a long-lifespan performance, which were all superior to the batteries using the ether-based electrolyte without PFPN. This study demonstrates an effective solution to solve the problems of flammable ether-based electrolytes and reactive lithium anodes, and it may contribute to the development of safe Li-S batteries.

Synthesis of graphene nanocomposites integrated with 3D bimetallic magnesium/cobalt metal-organic framework as anodic material for solid-state asymmetric supercapacitors

In this study, we have grown 3D porous bimetallic Mg/Co MOF in the presence of exfoliated graphene nanoplates (EGNPs) via a one-step in-situ hydrothermal process, where 1,3,5-benzenetricarboxylic acid (BTC) was used as an effective organic linker since it is cost-effective and EGNPs served as a conductive component. Morphological characterization of Mg/Co-BTC MOF@EGNP nanohybrid confirmed the homogeneous growth of ball-shaped Mg/Co-BTC MOF around the graphene nanoplates, while nitrogen adsorption-desorption analysis revealed large surface area with a high volume fraction of mesopores. This surface features is highly favorable for rapid ion/electron transportation that ensures high specific gravimetric capacitance (838 F/g) and noticeable rate capability (81 % capacitance retention). As-synthesized nanohybrid was used as anode material to construct a prototype all-solid-state asymmetric supercapacitors (ASC) device with a significantly high energy density of 73.82 Wh kg−1, a wide potential window of 0–1.7 V, admirable capacitance retention of 95.1 % after 8000 cycles, and long self-discharge time. Moreover, these capacitance performances also demonstrates the reliability of the as-synthesized poly vinyl alcohol (PVA)-Li2SO4 membrane as a separator-cum-electrolyte for fabrication of future leakage-proof ASCs for wearable electronics. This work can lead to manufacting innovation in the future.

Ruthenium Electrodeposition from Non-Aqueous Electrolytes Containing Divalent Ions

Ruthenium as a metal is characterized by interesting technological and aesthetic properties, which make it an ideal choice for many applications. Ruthenium is dark grey in appearance, it presents a reduced tendency to corrode, low contact resistance and high hardness. When applied in the form of thin films, it can be used in jewels production, protection of electrical contacts, deposition of barrier layers in microelectronics and manufacturing of interconnects in integrated circuits [1].Ruthenium layers can be advantageously deposited exploiting electrodeposition, typically from aqueous sulfamate based electrolytes containing the metal in the form of a complex known as μ-nitridobisaquatetrachlororuthenate [Ru2(μ-N)(H2O)2Cl8]3-. These baths are routinely used at the industrial level and provide good coatings at acceptable cathodic efficiencies. However, ruthenium tends to oxidize in aqueous environment and the resulting deposits can contain impurities or oxides. In addition, the electrodeposition of ruthenium in water-based electrolytes presents difficulties when thick and crack-free coatings are required.In an attempt to solve these limitations, the use of non-aqueous electrolytes for the deposition of ruthenium coatings has been proposed. The substitution of water with alternative solvents can potentially relieve the problem of ruthenium oxidation. Moreover, non-aqueous electrolytes are characterized by wide potential windows, which translate into a reduction in the entity of parasitic hydrogen evolution reactions. Consequently, the properties of the deposit obtained can be potentially improved. In the context of non-aqueous electrolytes, ruthenium has been deposited from water and air stable ionic liquids [2, 3] and from deep eutectic solvents [4].With respect to our previous paper on the deposition of ruthenium [4], where the metal was deposited from the (IV) oxidation state, the present work describes a diametrically different approach. Indeed, we investigate the electrodeposition of ruthenium layers from a non-aqueous electrolyte based on ethylene glycol and containing the metal in its divalent state. The (II) oxidation state is obtained by reducing trivalent RuCl3 with ascorbic acid. A complete physical and electrochemical characterization of the resulting electrolytes is performed, demonstrating the reduction of Ru(III) to Ru(II). The deposition of thin and thick layers is attempted and the resulting coatings are characterized to exclude the possible presence of oxides or other secondary phases. Finally, the possible application of ruthenium layers for electrical contacts protection is evaluated.[1] R. Bernasconi and L. Magagnin, J. Electrochem. Soc. 166(1), D3219-D3225 (2019)[2] O. Raz, G. Cohn, W. Freyland, O. Mann and Y. Ein-Eli, Electrochim. Acta 54, 6042 (2009)[3] O. Mann, W. Freyland, O. Raz and Y. Ein-Eli, Chem. Phys. Lett. 460, 178 (2008)[4] R. Bernasconi, A. Lucotti, L. Nobili and L. Magagnin, J. Electrochem. Soc. 165(13), D620-D627 (2018)

New Liquid Electrolytes Consisting of Li Salts and Urea Derivatives for Li-Ion Batteries

Deep eutectic solvents are mixtures that exhibit melting points much lower than those of the endmembers due to the molecular interactions. Deep eutectic solvents attracted attention because high melting point compounds are available as flame-resistance solvents.1 However, the stable operation of Li-ion batteries (LIBs) with deep eutectic electrolytes (DEEs) is still challenging probably due to their high protonic nature and consequent narrow potential window.2 To develop Li-ion DEEs with a wide potential window, we investigated DEEs based on lithium bis(fluorosulfonyl)amide (LiFSA) and a series of urea derivatives to clarify the correlation between compound structure and electrolyte properties. Furthermore, we examined the electrode performances of the Li4Ti5O12 (LTO) negative electrode and LiNi1/3Co1/3Mn1/3O2 (NCM) positive electrode in the DEEs.To prepare DEEs, urea derivatives, such as urea, 1-methylurea, 1,3-dimethylurea, 1,1-dimethylurea, and tetramethyl urea are mixed with LiFSA at molar ratios of 1:2 or 1:4 at room temperature. The oxidation and reduction stability was evaluated by linear sweep voltammetry (LSV) in three-electrode cells with Pt foil as the working electrode. Galvanostatic charge-discharge tests were performed in three-electrode cells with LTO or NCM working electrodes and activated carbon counter electrodes.The prepared LiFSA:urea derivative (1:4) mixtures (LiFSA:urea, LiFSA:1,3-dimethylurea, and LiFSA:tetramethylurea) became transparent liquids at room temperature. Moreover, LiFSA:1,3-dimethylurea and LiFSA:tetramethylurea were clear liquid at even in 1:2 mixtures. Using the five DEEs, we evaluated their electrolyte properties. Figure 1 shows the LSV curves of the DEEs. Among the five deep eutectic liquids, LiFSA:1,3-dimethylurea (1:2) exhibited the widest potential window of 4.49 V, showing an even wider potential window than electrolytes with non-protonic tetramethyl urea.Figure 2a displays the charge-discharge curves of LTO electrodes in the DEEs. The LiFSA:urea (1:4) electrolyte cell exhibits a large irreversible capacity, and its initial reversible capacity is 228 mAh g-1, significantly larger than the theoretical capacity. This indicates that side reactions possibly takes place in addition to the LTO charge-discharge reaction. On the other hand, the LiFSA:1,3-dimethylurea (1:2) electrolyte demonstrates stable and reversible charge-discharge for 50 cycles, with an initial discharge capacity of 179 mAh g-1, which is close to the theoretical capacity. The LiFSA:tetramethylurea cell showed lower cycle stability than the LiFSA:1,3-dimethylurea cell, possibly due to electrolyte precipitation during cycling because LiFSA:tetramethylurea (1:2) electrolyte is an almost saturated solution.Using the LiFSA:1,3-dimethylurea (1:2) DEE, we further evaluated the electrochemical performance of the NCM electrode as shown in Figure 2b. The NCM electrode showed reversible charge-discharge behavior over 10 cycles with moderate capacity of 75.7 mAh g-1. These results demonstrate the potential applicability of the DEE to 3 V-class LIBs. In the presentation, we will also discuss the optimization of LiFSA concentration to improve battery properties and the observation of the formation of surface films on the electrodes in DEEs.

Improvement of Ionic Conductivity in Li7La3Zr2O12 (LLZO) Solid Electrolyte By Doping with Aluminum/Tungsten

Recently, there has been increasing interest in solid electrolytes, which are the most important materials in all-solid-state lithium-ion batteries. Among all solid electrolytes, garnet-type Li7La3Zr2O12 (LLZO) has been proven to be one of the most promising electrolytes due to its high Li+ conductivity, wide potential window, and electrochemical stability towards metallic lithium anode. In particular, cubic garnet-type LLZO solid electrolytes have received a lot of attention for the development of high-performance all-solid-state batteries with safety, energy density, and long cycle life. In this study, we synthesized LLZO solid electrolyte powders with garnet structure and determined the optimal composition and sintering temperature by adding Al/W to form a stable cubic phase.In this study, Al or W-doped LLZO were prepared by a post-doping method. In this process, LLZO powder was first prepared, and then mixed with Al2O3 or WO3 powders to produce doped LLZO ceramic electrolytes, respectively. During this process, the doped ions entered the LLZO lattice, increasing the lithium ion transport channels and promoting lithium ion conductivity. The sintering time, crucible, and sintering temperature were adjusted to investigate the optimal process conditions of the post-doping method. As a result, the doped solid electrolyte exhibited high lithium ion conductivity and low activation energy. Using the high lithium ion conductivity and broad electrochemical stability window of the Al or W doped LLZO SSE, the (NCM622)/(Al or W doped-LLZO) cell delivered a steady cycle for 100 cycles at 0.1C. The Al or W doped-LLZO prepared in this study showed advantages of high conductivity, simple preparation process, high reproducibility, and low cost, which provides technical support and reference for further application of garnet-type SSEs in solid-state batteries with high energy density.

The Electrode/Electrolyte Interface in MXene-Based Electrochemical Capacitors

The operating voltage of electrochemical capacitor (EC) in aqueous medium is considerably limited due to the theoretical stability of water (1.23V). Hence, the delivered energy density of such systems is restricted compared to that of batteries. A traditional approach to tackle this issue is to focus on improving the capacitance rather than the working voltage of ECs. Especially, combining traditionally used carbons with pseudocapacitive materials has been investigated by many researchers. Adopting this strategy improves the delivered capacity of the system, but key metrics such as a power performance and cycle life of ECs may face a serious failure. The slow nature of faradaic reactions affects the frequency response, while the parasitic activities downgrades the favorable cyclability of the device. Hence, a realistic pathway to improve the energy performance of ECs must be taken. Transition metal carbides, carbonitrides, and nitrides (MXenes) are a new family of 2D layered materials. They have the general formula of Mn+1Xn, in which M indicates the transition metal, like Ti, Mo, Nb, etc., and X is carbon or nitrogen. Considering favorable properties such as a high conductivity and the ability of cation intercalation, many ECs designs based on MXenes have been reported. Nevertheless, there is a lack of clear elucidation of the charge storage mechanism in these materials. Here, the interface of electrode-electrolyte was studied to gain a better insight into the hydrogen storage mechanism and overpotential of MXenes (Ti3C2Tx) in acidic and neutral media. It has been found that MXene-based ECs are suffering from an unbalanced capacitive performance between negative and positive electrodes. Especially, a low capacitance in the positive potential range limits the cell voltage to 0.8V and 1.3V in 1M H2SO4 and 1M Li2SO4, respectively. To extend the cell voltage, self-standing composites based on 3D graphene and Ti3C2Tx were designed. Interestingly, it was observed that during the negative polarization, a significant redox couple activity was observed at the surface of 3DG/ Ti3C2Tx composite electrode. The working potential of the positive electrode was enlarged using micro/mesoporous Black Pearl (BP2000) as electrode material. The realized asymmetric cell was operated in a wider potential window. A higher expansion was realized after balancing the charge of both electrodes. The addition of redox-active salt (KI) to the electrolyte medium improved the capacitive performance of the positive electrode, due to the activity of iodide/iodine species. Excessive increase of the positive electrode capacity was further equalized by balancing the mass of electrodes. In the neutral medium, an asymmetric design of the cell based on Ti3C2Tx (negative electrode) and BP2000 (positive electrode) allowed the cell to operate in a broad range of voltage (up to 2V) with a stable cycling (more than 7000 cycles). The prepared electrodes were characterized using different physiochemical techniques, including XRD, XPS, BET, and SEM analyses. For the electrochemical characterization in two and three-electrode cells, electrodes in the form of pellets or self-standing discs were utilized. The performance of EC cells was studied by cyclic voltammetry, galvanostatic charge-discharge, and electrochemical impedance spectroscopy.

Investigating the Impact of Ag Nanoparticles on N and S Co‐Doped TiO2 for Battery‐Type Supercapacitor Application

AbstractIn this work, we demonstrate a successful synthesis of heteroatom co‐doped TiO2 decorated with Ag nanoparticles using a direct combustion approach. These materials serve as a high‐performance active layer for advanced battery‐type supercapacitors. Among all the investigated materials, N,S co‐doped TiO2 nanoparticles and Ag/N,S co‐doped TiO2 nanocomposite exhibited impressive specific capacitances of 360 and 480 F g−1 at a current density of 1 A g−1. Moreover, we employed Ag/N,S co‐doped TiO2 nanocomposite as symmetric supercapacitor in a wide potential window of −1 to 1 V. The symmetric device demonstrated a specific capacitance of 183 F g−1 at 3 A g−1 with an energy density of 105 Wh kg−1 at a power density of 6 kW kg−1. One of the most promising aspects of this study was the high cyclic stability of the device, with capacity retention of 80 % when tested for 3000 discharge cycles at 3 A g−1.The improved electrochemical performance of Ag nanoparticle decorated N,S co‐doped TiO2 structure confirms the synergistic behavior of each component in the nanocomposite. These results indicate the remarkable durability of the device. Additionally, the materials used in this work are environmentally friendly, making them attractive candidates for battery‐type supercapacitors.

Adjusted Preferential Adsorption of Intermediates via Regulation of the Electronic Structure during the Electrocatalytic CO2 Reduction Process.

The surface electronic structures of catalysts play a crucial role in CO2 adsorption and activation. Here, sulfur vacancies are introduced into CuInS2 nanosheets (Vs-CuInS2) to evaluate the effect of electronic structures at the surface-active sites on the electrochemical CO2 reduction reaction (CO2RR). Vs-CuInS2 exhibits a significant disparity in the highest FEformate/FECO (6.50) compared to that of CuInS2 (1.86). Specifically, the maximum current density (Jmax) of carbon products on Vs-CuInS2 is 78.78 mA cm-2, and a Faraday efficiency of carbon products (FEcarbonproducts) of ≥80% is achieved in 600 mV wide potential windows. In situ Raman measurements and density functional theory calculations elucidate the origin of the apparent alterations in the carbon product selectivity. The introduction of sulfur vacancies realizes the controllable regulation of the local electronic density around the metal active sites, inducing the transformation of *COOH and *OCHO from competitive adsorption on CuInS2 to specific adsorption on Vs-CuInS2. In addition, the regulation of electronic structures on Vs-CuInS2 inhibits *H adsorption. This work reveals the transfer of adsorption of CO2RR intermediates via regulation of the electronic structure, complementing the understanding of the mechanism for the enhanced CO2RR.

Hydrothermal growth of FeMoO4 nanosheets on electrospun carbon nanofibers as freestanding supercapacitor electrodes

In this study, an electrospinning method was used to produce highly conductive freestanding carbon nanofibers (CNFs). The freestanding CNFs are compatible with hierarchical growth techniques, such as hydrothermal processes, for the nanostructure engineering of supercapacitor electrodes with enhanced electrochemically active sites. Therefore, the flower-like FeMoO4@CNF nanosheets were investigated to improve the electrochemical performance using aqueous and neutral electrolytes (Na2SO4 and K2SO4). The optimized FeMoO4@CNF electrode exhibits areal capacitances of 252 and 220 mF·cm−2 at a high current density of 2.5 mA·cm−2 with Na2SO4 and K2SO4 electrolytes, respectively. The wide potential window (1.6 V) of the symmetric supercapacitor delivered maximum energy densities of 22.4 and 19.6 μWh·cm−2 at a power density of 2 mW·cm−2 for Na2SO4 and K2SO4 electrolytes, respectively.

RGO-Induced Flower-like Ni-MOF In Situ Self-Assembled Electrodes for High-Performance Hybrid Supercapacitors.

Currently, the primary bottlenecks that hinder the widespread application of supercapacitors are low energy density and narrow potential windows. Herein, the hybrid supercapacitor with high energy density and wide potential window is constructed via an in situ self-assembly method employing RGO-induced flower-like MOF(Ni). Benefiting from the synergistic effect between RGO and MOF(Ni), the interfacial interactions are effectively improved, and the contact area with the electrolyte is enhanced, which increases the ion transfer kinetics and overall electrochemical performance. The MOF(Ni)@RGO electrode exhibits a specific capacitance of 1267.73 F g-1 at a current density of 1 A g-1. Crucially, the assembled MOF(Ni)@RGO//BC with a broad potential window and good stability employing a MOF(Ni)@RGO anode and biomass carbon cathode, combined with a 2 M PVA-KOH gel-electrolyte, achieves a maximum energy density of 70.16 Wh kg-1 at a power density of 2200.09 W kg-1, outperforming most reported supercapacitors. This hybrid supercapacitor exhibits excellent stability and high energy density, providing a novel strategy for further large-scale applications.

Anion-Mediated In Situ Reconstruction of the Bi2MoO6 Precatalyst for Enhanced Electrochemical CO2 Reduction over a Wide Potential Window.

Electrochemical CO2 reduction reaction (eCO2RR) is a viable approach to achieve carbon neutrality. Bismuth-based electrocatalysts demonstrate exceptional selectivity in CO2-to-formate conversion, but their reconstruction mechanisms during the eCO2RR remain elusive. Herein, the reconstruction processes of bismuth molybdate (Bi2MoO6) nanoplates are elucidated during the eCO2RR. Operando and ex situ measurements reveal the in situ partial reduction of Bi2MoO6 to Bi metal, forming Bi@Bi2MoO6 at negative potentials. Meanwhile, CO32- ions in the electrolyte spontaneously exchange with MoO42- in Bi2MoO6. The obtained Bi@Bi2MoO6/Bi2O2CO3 delivers a formate Faradaic efficiency (FE) of 95.2% at -1.0 V. Notably, high formate FEs (>90%) are maintained within a wide 500 mV window. Although computational calculations indicate a higher energy barrier for *OCHO formation on Bi2O2CO3, the prevention of excessive reduction to metal Bi significantly enhances long-term stability. Furthermore, the CO32- ion exchange process occurs in various 2D Bi-containing precatalysts, which should be emphasized in further studies.

Decoupled Design for Highly Efficient Perchlorate Anion Intercalation and High-Energy Rechargeable Aqueous Zn-Graphite Batteries.

Seeking new cathode chemistry with high onset potential and compatibility with electrolytes has become a challenge for aqueous Zn ion batteries. Anion intercalation in graphite (4.5V vs Li+ /Li) possesses the potentiality but usually shows a competitive relationship with oxygen evolution reaction (OER) in aqueous solutions. Herein, a decoupled design is proposed to optimize a full utilization of perchlorate ion intercalation in graphite cathode by pH adjustment. Benefiting from the decoupled design, high Coulombic efficiency is obtained by decelerating the kinetic of OER in acidic media. The decoupled Zn-graphite battery exhibits a wide potential window of 2.01V, as well as an attractive energy density of 231Whkg-1 . In addition, a Zn-graphite battery with insertion is assembled, which demonstrates the capability of the proposed decoupled strategy to integrate novel electrode chemistries for high-performance aqueous Zn-based energy storage systems.