Cycling Durability Research Articles

Flexible and free-standing MXene decorated biomass-derived carbon cloth membrane anodes for superior lithium-ion capacitors

Two-dimensional transition metal materials, MXenes, have attracted tremendous attention in energy storage applications due to their layered structure, good electrical conductivity, and abundant functional groups. In this work, Ti3C2Tx MXene nanosheets and carbon nanotubes (CNTs) were uniformly sprayed and successfully loaded on the cotton nonwoven fabric-derived carbon cloth (CC) substrate by electrostatic self-assembly. The as-prepared flexible MXene-CNTs-CC membrane electrodes with enlarged interlayer spacing and high conductivity fabric support exhibited excellent electrochemical performance. In terms of lithium-ion batteries, the optimized MXene-CNTs-CC anode delivered an ultrahigh initial discharge capacity of 2277.5 mAh g−1 at 0.1 A g−1 along with notable cyclability (1149.8 mAh g−1 after 100 cycles) and rate capability (544.1 mAh g−1 after 200 cycles at 2 A g−1) in half cells. The full cells assembled with LiCoO2 cathode also displayed good cycling stability with a high reversible discharge capacity of 833.5 mAh g−1 after 100 cycles at 0.1 A g−1. Remarkably, the further constructed lithium-ion capacitors with the designed porous carbon nanofiber cathode could maintain energy densities of 121.5 to 20.8 Wh kg−1 with the corresponding power densities of 125 to 12,500 W kg−1, and achieved capacitance retention of 76.3 % after 10,000 cycles at 1 A g−1, demonstrating excellent long-term cycle durability.

Optimizing Reversible Phase‐Transformation of FeS2 Anode via Atomic‐Interface Engineering Toward Fast‐Charging Sodium Storage: Theoretical Predication and Experimental Validation

AbstractSodium‐storage performance of pyrite FeS2 is greatly improved by constructing various FeS2‐based nanostructures to optimize its ion‐transport kinetics and structural stability. However, less attention has been paid to rapid capacity degradation and electrode failure caused by the irreversible phase‐transition of intermediate NaxFeS2 to FeS2 and polysulfides dissolution upon cycling. Under the guidance of theoretical calculations, coupling FeS2 nanoparticles with honeycomb‐like nitrogen‐doped carbon (NC) nanosheet supported single‐atom manganese (SAs Mn) catalyst (FeS2/SAs Mn@NC) via atomic‐interface engineering is proposed to address above challenge. Systematic electrochemical analyses and theoretical results unveil that the functional integration of such two type components can significantly enhance ionic conductivity, accelerate charge transfer efficiency, and improve Na+‐adsorption capability. Particularly, SAs Mn@NC with Mn‐Nx coordination center can reduce the decomposition barrier of Na2S and NaxFeS2 to further accelerate reversible phase transformation of Fe/Na2S→NaFeS2→FeS2 and polysulfides decomposition. As predicted, such FeS2/SAs Mn@NC showcases outstanding rate capability and fascinating cyclic durability. A sequence of kinetic studies and ex situ characterizations provide the comprehensive understanding for ion‐transport kinetics and phase‐transformation process. Its practical use is further demonstrated in sodium‐ion full cell and capacitor with impressive electrochemical capability and excellent energy‐density output.

Band Engineering of Mn-P Alloy Enables HER-suppressed Aqueous Manganese Ion Batteries.

Aqueous manganese ion batteries hold potential for stationary storage applications owing to their merits in cost, energy density, and environmental sustainability. However, the formidable challenge is the instability of metallic manganese (Mn) anodes in aqueous electrolytes due to severe hydrogen evolution reaction (HER), which is more serious than the commonly studied Zn metal anodes. Moreover, the mechanism of HER side reactions has remained unclear. Herein, we design a series of Mn-P alloying anodes by precisely regulating their energy band structures to mitigate the HER issue. It is found that the serious HER primarily originates from the spontaneous Mn-H2O reaction driven by the excessively high HOMO energy level of Mn, rather than electrocatalytic water splitting. Owing to a reduced HOMO energy level and enhanced electron escape work function, the MnP anode achieves an evidently enhanced cycle durability (over 1000 hours at a high current density of 5 mA cm-2). The MnP||AgVO full cell with an N/P ratio of 4 exhibits better rate capability and extended cycle life (7000 cycles) with minimal capacity degradation than the cell using metallic Mn anode (less than 100 cycles). This study provides a practical approach for developing highly durable aqueous Mn ion batteries.

Band Engineering of Mn‐P Alloy Enables HER‐suppressed Aqueous Manganese Ion Batteries

AbstractAqueous manganese ion batteries hold potential for stationary storage applications owing to their merits in cost, energy density, and environmental sustainability. However, the formidable challenge is the instability of metallic manganese (Mn) anodes in aqueous electrolytes due to severe hydrogen evolution reaction (HER), which is more serious than the commonly studied Zn metal anodes. Moreover, the mechanism of HER side reactions has remained unclear. Herein, we design a series of Mn−P alloying anodes by precisely regulating their energy band structures to mitigate the HER issue. It is found that the serious HER primarily originates from the spontaneous Mn‐H2O reaction driven by the excessively high HOMO energy level of Mn, rather than electrocatalytic water splitting. Owing to a reduced HOMO energy level and enhanced electron escape work function, the MnP anode achieves an evidently enhanced cycle durability (over 1000 hours at a high current density of 5 mA cm−2). The MnP||AgVO full cell with an N/P ratio of 4 exhibits better rate capability and extended cycle life (7000 cycles) with minimal capacity degradation than the cell using metallic Mn anode (less than 100 cycles). This study provides a practical approach for developing highly durable aqueous Mn ion batteries

Promoting Reaction Kinetics of the Air Cathode for Neutral Zinc-Air Batteries by the Photothermal Effect.

Rechargeable neutral zinc-air batteries are attracting enormous research interest due to their long lifetime and low cost. However, the sluggish kinetics of the air cathode in the neutral electrolyte reduces the catalytic performance and impedes the power density and energy efficiency of zinc-air batteries. In this work, we propose a universal, sustainable, and effective approach to improve the kinetics of the air cathode through a solar-energy-induced photothermal effect. By illumination of the cost-effective carbon-black-based cathode, the temperature of the air cathode increases from room temperature to 40.5 °C, thereby accelerating the kinetics for the electrocatalytic reaction and reducing the interfacial resistance of the zinc-air battery. Attributed to the sunlight-promoted reaction kinetics, the neutral zinc-air battery exhibits a higher power density of 2.89 mW cm-2 and longer cycling durability over 250 h, 116 and 156% times the one without light illumination, significantly improved in contrast to the one without light illumination. Furthermore, we demonstrated solar energy-driven and solar-enhanced charging in the daytime and discharging at night, potentially applying in distributed energy storage applications. The proposed sustainable solar-energy-promoted reaction kinetics of air cathodes will drive the development of efficient zinc-air batteries and also inspire the rational design of electrocatalytic electrodes in other electrochemical devices.

Consolidating the Oxygen Reduction with Sub-Polarized Graphitic Fe-N4 Atomic Sites for an Efficient Flexible Zinc-Air Battery.

The effectuation of the Zn-air battery (ZAB) is appealing for active and durable catalysts to kinetically drive the sluggish cathodic oxygen reduction reaction (ORR). Atomic metal-Nx-C sites are widely witnessed with Pt-like activity, but their demetalations still severely restrict the durability in ORR. Here we have profiled an ordered hierarchical porous carbon supported Fe-N4 single-atom (FeNC) catalyst by a template derivation method for efficient ORR and flexible ZAB studies. The FeNC structure is observed with a sub-polarized graphitic Fe-N4 coordination with a shortened Fe-N bond for potentially consolidating the ORR, together with the hierarchical porous matrix for kinetical mass transfer. Resultantly, the optimized FeNC catalyst showcases Pt-beyond alkaline ORR activity (E1/2 = 0.95 V) with long-term durability for 100 h, delivering the flexible ZAB device with high power density (251 mW cm-2) and durable cycle life (80 h). This research underscores the criterion in rationalizing active and robust ORR catalysts through metal-nitrogen bond modulation.

Zeolitic imidazolate framework@graphene oxide nanocomposites for efficient supercapacitor electrodes

Despite advancements in nanoscale electrode materials, the pursuit of dependable, effective, and environmentally sound supercapacitors continues. This study explores the potential of zeolitic imidazolate framework@graphene oxide (ZIF@GO) nanocomposites as a viable option by revealing their improved electrochemical performance, including enhanced charge storage capacity and prolonged cycling stability. The ZIF-8@GO electrode exhibited an exceptional specific capacitance of 1372.67F/g at 1 A/g, indicating remarkable energy storage capacity. Furthermore, it showed exceptional cycling stability and durability by maintaining 96.02% of its capacitance after 20,000 cycles. To further evaluate ZIF-8@GO for energy storage, an asymmetric supercapacitor was assembled using the engineered electrode and activated carbon as the cathode and anode, respectively. The ZIF-8@GO nanostructure device demonstrated outstanding energy storage capability, maintaining a high specific capacitance of 165.29F/g at 1 A/g. Additionally, the device exhibited remarkable stability and endurance after 20,000 cycles, retaining 87.47% of its initial value. The promising electrochemical performance and ability of ZIF-8@GO nanocomposite to maintain capacitance across multiple cycles suggest a potential for advanced supercapacitor electrode materials.

A robust floating oxygen-doped graphitic carbon nitride sheet for efficient photocatalytic CO2 conversion

Photocatalytic CO2 reduction offers a promising approach for converting CO2 into valuable chemicals. However, typical conversion systems suffer from inefficient CO2 mass transfer and complex recycling processes. In this study, we developed a floating sheet as a robust photocatalytic CO2 conversion system by integrating graphitic carbon nitride (CN) nanosheets onto polytetrafluoroethylene (PTFE) fiber membrane, followed by oxygen (O) doping into the CN (CN-O) via oxygen-plasma treatment. The floatable CN-O/PTFE sheet exhibits slight wettability in water under 0.25 MPa of CO2 pressure in our reactor system, facilitating the delivery of dissolved CO2 to the CN-O photocatalyst surface. O-doping enhances the visible light absorption and improves the separation and transport efficiency of photogenerated electrons and holes due to O-doping-induced states in CN. Consequently, the floating CN-O/PTFE system achieves an exceptional photocatalytic CO2 conversion rate of 102.3 μmol g-1h-1, approximately 4.8 times higher than a conventional CN-powder dispersion system in water. Moreover, the sheet demonstrates excellent cycling durability, with no significant exfoliation of the catalytic layer or reduction in CO2 photoreduction activity after 20 consecutive cycles. This study presents a novel approach to designing photocatalytic systems for efficient CO2 conversion.

Optimizing Sodium Ion Adsorption Through Robust d–d Orbital Modulation for Efficient Capacitive Deionization

AbstractUnraveling the fundamental mechanisms of sodium ion adsorption behavior is crucial for guiding the design of electrode materials and enhancing the performance of capacitive deionization systems. Herein, the optimization of sodium ion adsorption is systematically investigated through the robust d–d orbital interactions within zinc‐doped iron carbide, facilitated by a novel liquid nitrogen quenching treatment. Liquid nitrogen quenching treatment can enhance the coordination number, strengthen d–d orbital interactions, promote electron transfer, and shift the d‐band center of Fe closer to the Fermi level, thereby enhancing sodium ions adsorption energy. Consequently, the obtained electrode material achieves a superior gravimetric adsorption capacity of 121.1 mg g−1 and attractive cyclic durability. The adsorption capacity is highly competitive compared to the vast majority of related research works in the field of capacitive deionization. Furthermore, sodium ion adsorption/desorption mechanisms are substantiated through ex situ techniques, revealing dynamic atomic and electronic structure evolutions under operational conditions. This work demonstrates that optimizing sodium ion adsorption via robust d–d orbital modulation enabled by liquid nitrogen quenching treatment is an effective approach for developing efficient capacitive deionization electrode materials.

Enabling High‐Rate and Long‐Cycling Zinc–Air Batteries with a ΔE = 0.56 V Bifunctional Oxygen Electrocatalyst

AbstractZn–air batteries (ZABs) are promising next‐generation energy storage devices due to their low cost, intrinsic safety, and environmental benignity. However, the sluggish kinetics of the cathodic reactions severely limits the ZAB performances in practical use, calling for high‐efficiency bifunctional oxygen reduction and evolution electrocatalysts. Herein, an ultrahigh‐active bifunctional electrocatalyst is developed with a record‐low ΔE of 0.56 V, significantly outperforming the noble‐metal‐based benchmark (Pt/C+Ir/C, ΔE = 0.77 V) and many other reported bifunctional electrocatalysts (mostly ΔE ≥ 0.60 V). The nanoscale composite of Fe‐based single‐atom sites and nanosized layered double hydroxides endows the bifunctional electrocatalyst with high conductivity and a large active surface that afford strengthened electron conduction and ion transport pathways. Furthermore, a remarkable improvement in stability is realized following the current division principle. ZABs with the bifunctional electrocatalyst deliver a high peak power density of 198 mW cm−2 and excellent cycling durability for over 6000 cycles. Moreover, ampere‐hour‐scale ZABs are constructed and cycled under 1.0 A and 1.0 Ah conditions. This work breaks the activity record for bifunctional oxygen electrocatalysis and expands the potential of ZABs for sustainable energy storage.

Fe3Co nanoparticles embedded carbon nanotube complex as effective bifunctional electrocatalysts for rechargeable zinc-air batteries

Fe3Co nanoparticles have been successfully embedded within ZIF-8 derived carbon nanotube complex using a simple solvent-heated self-assembly-pyrolysis strategy, it acts as an efficient ORR/OER bifunctional electrocatalyst and showed outstanding performance of excellent catalytic activity for ORR (E1/2 = 0.87 V at 0.1 M KOH) and OER (the overpotential at 10 mA cm−2 is 390 mV at 1 M KOH). Density functional theory (DFT) demonstrates that the introduction of iron and cobalt atoms significantly impacted on the adsorption energies of the reactive intermediates. In particular, the combination of cobalt and iron exhibited significantly enhanced ORR/OER activities, revealing an enhanced effect of synergistic interaction of FeCo site for bifunctional properties. It is used as Fe3Co1−NC in aqueous zinc-air battery (ZAB) and exhibited a high open-circuit voltage of 1.52 V, power density of 189.8 mW cm−2, and long cycle durability of 400 h. Flexible ZABs assembled exhibit high power density (81.59 mW cm−2) and long cycling durability (90 h).

Hierarchical Flower Array NiCoOOH@CoLa‐LDH Nanosheets for High‐Performance Supercapacitor and Alkaline Zn Battery

AbstractNickel oxyhydroxide based energy storage materials have been largely confined by insufficient exposure of active sites which results in low energy efficiency and poor stability. In order to resolve the problems, hierarchical flower array heterostructure NiCoOOH@CoLa‐LDH (denoted as NC@CL) nanosheets are designed with NiCo oxyhydroxide (NiCoOOH, denoted as NC) being tightly covered on CoLa layered double hydroxide (CoLa‐LDH, denoted as CL) nanosheet. This rational design creates more active sites, enlarges the electrode‐electrolyte contact area, improves electron conductivity, and prevents agglomeration during the cycling charge–discharge processes. Density functional theory calculations and differential charges concurrently illustrate that heterostructure formation optimizes the reaction kinetics and promotes electron redistribution. Benefiting from the heterogeneous structure and rich electro‐active sites caused by NC, NC@CL displays outstanding reversible specific capacitance (3228 F g−1 at 1 A g−1). The aqueous rechargeable alkaline Zn battery NC@CL//Zn exhibits a high capacity of 381.1 mA h g−1 at 0.5 A g−1 and cycling durability (98% capacity retention after cycling at 5 A g−1 for 2000 cycles). The excellent electrochemical performances indicate that NC@CL has great application potential as electrode material for aqueous energy storage device.

Multilayer Bionic Tunable Strain Sensor with Mutually Non‐Interfering Conductive Networks for Machine Learning‐Assisted Gesture Recognition

AbstractFlexible strain sensors capable of acquiring tiny mechanical signals and attaching to various irregular surfaces are becoming prevalent in physiological measurement, soft robotics, and human‐machine interaction. However, the advancement of flexible strain sensors is substantially impeded by the intrinsic compromise between sensitivity and the range of detectable signals. Inspired by the multilayer structure of nacre in nature, a carbon nanotubes (CNTs)/graphene (GR)/graphene (GR)/thermoplastic polyurethane (TPU) mat (CGGTM) is prepared by electrospinning and high‐pressure spraying technology. By designing a multilayer structure with mutually non‐interfering conductive networks, the resulting CGGTM possesses a low detection limit (0.05% strain), high sensitivity (gauge factor, GF > 152537), large detection range (up to 364% strain), fast response/recovery time (80 ms/100 ms), and excellent cyclic durability (up to 1000 cycles). Furthermore, the CGGTM also exhibits satisfactory triboelectric performances when assembled into a triboelectric nanogenerator (TENG, 3 × 3 cm2), including high triboelectric output (open‐circuit voltage Voc = 135.4 V, short‐circuit current Isc = 1.25 µA) and power density (88 mW m−2), enabling reliable power supply, self‐powered sensing, and pulse monitoring capability. Finally, CGGTM is successfully applied to the collection of biological signals and multi‐gesture motion recognition assisted by machine learning algorithms, which holds promise for intelligent interaction with gestures in the future.

Seaweed waste in eco-friendly construction materials: Valorization of Sargassum ash as a mineral addition in fiber cements

Many coastal regions have recently faced significant challenges due to the excessive accumulation of sargassum. This genus of brown marine algae generates greenhouse gases such as methane and carbon dioxide during decomposition, as well as toxic gases such as hydrogen sulfide and ammonia. The substantial influx of these algae on shores brings far-reaching impacts on the environment, climate, health, and the economy. One way to mitigate these impacts is by using this biomass for energy production and applying the resulting ash as an alternative material in the construction industry. As such, this study aims to analyze the feasibility of sargassum ash as a replacement for limestone in fiber cement. This not only offers an environmentally responsible solution for its disposal, but also adds economic value to a material commonly seen as a waste. Several analyses were conducted on the physical and mechanical properties of fiber cement with varying percentages of limestone replaced by sargassum ash (0, 25, 50, 75, and 100 %), as well as its durability and Life Cycle Assessment (LCA). The fiber cement with 100 % sargassum ash exhibited a 74 % increase in specific energy compared to the fiber cement without the ash after accelerated aging. This mix design also presented better environmental performance in 15 of the 18 impact categories. The results demonstrate that ash holds potential as an alternative material in fiber cement manufacturing.

Tailoring Cationic Cobalt Vacancies in Molybdenum-Cobalt Selenide Derived from POM@ZIF-67 for Enhanced Electrocatalysis in Lithium-Oxygen Batteries.

Slow reaction kinetics during redox reactions limits the utilization of the high theoretical energy density of lithium-oxygen batteries (LOBs). Vacancy engineering, a potential strategy for modulating active sites, is critical in the development of high performance catalysts. This study investigates cobalt vacancies in Mo-CoSe2 nanoparticles created by selenization of phosphomolybdic acid (POM) embedded into zeolitic imidazolate framework-67 (ZIF-67). The nanomaterial exhibits an outstanding electrochemical performance, characterized by high specific capacitance and excellent cycle durability. The LOBs with cobalt vacancies in the Mo-CoSe2 electrode material exhibit a discharge capacity of 21 836 mAh g-1 at a current density of 100 mA g-1 and exhibit stable cycling performance over 194 cycles at 300 mA g-1. Additionally, density functional theory (DFT) calculations suggest that the presence of cobalt vacancies increases the distance between the surface selenium atoms and the subsurface cobalt atoms. In addition, cobalt vacancies modify the electronic structure of the d-orbitals, lowering the energy barriers of the reaction and accelerating the reaction kinetics by improving the adsorption of the reactants. The research introduces a strategy for the rational design of efficient cathode materials in LOBs.

Biomass-Derived Carbon With Large Interlayer Spacing for Anode of Potassium Ion Batteries.

Potassium-ion batteries (PIBs) are emerging as powerful candidate for grid-oriented energy storage owing to their potentially low cost. Carbon is considered the promising anode for PIBs on the basis of its high conductivity and abundant sources. The biggest challenge confronted by carbon anodes lies in insufficient cycle life as well as rate capability, resulting from the limited interlayer spacing of the sp2-hybrid carbon incompatible with the large-radius potassium. Herein, a biomass-derived carbon with a large interlayer spacing of 0.44nm is fabricated via a zinc-assisted pyrolysis synthesis. The unique structure endows the carbon with superior capacity, rate capability, and cycle durability. The large interlayer spacing of carbons can promote fast potassium diffusion and alleviate the volume expansion during potassiation, conferring those rate capabilities and cycleability. The interconnected network structure is also able to shorten both the transport distances of electrons and ions. The demonstration exemplifies an advanced carbon for anodes of PIBs for energy storage applications.

Boosting the Charge Storage Capability of Bi2TeO5 Cathode Using Iodide Ions in Aqueous Zinc-Based Batteries System.

As insertion-type cathode materials of aqueous Zn-based batteries (ABs), bismuth chalcogenides/oxychalcogenides exhibits relatively limited capacities in ZnSO4 baseline electrolyte. This work finds that Bi2TeO5 (BTO) cathode with pre-added I- electrolyte additive can simultaneously achieve conversion and insertion chemistries, which enables aqueous BTO-Zn batteries to deliver an extraordinary electrochemical performance. As shown in the experiment results, the BTO cathode showcases an ultrahigh specific capacity of 534.9mA h g-1 at 0.5 A g-1, excellent rate capability (237.3mA h g-1 at 10 A g-1). In the estimation of cyclic durability, the capacity of the BTO cathode decreases from 271.2 to 171.1mA h g-1 during 2000 cycles at 10 A g-1.

Polymerization of redox-active alizarin in biomass porous carbon with enhanced cycling stability for supercapacitor

Redox-active organic molecules have optimistic application prospects in energy storage due to their high theoretical capacitance, designable electrochemical activity and environmental friendliness. However, low conductivity and solubility in electrolyte severely hinder their redox activity. Here, alizarin molecules containing carbonyl and phenolic hydroxyl are encapsulated in biomass-derived porous carbon, and stable alizarin polymers are further grown on porous carbon substrate by electrochemical polymerization. Porous carbon as conductive network can improve electron transport properties, and provide suitable accommodation environment for confinement and polymerization of alizarin. The electrochemical polymerization strategy on carbon substrate allows alizarin to be connected by rigid C-O-C bond, which inhibits the dissolution of organic monomers while maintaining redox activity. The optimized polyalizarin/porous carbon composite (PAZ/PC-0.5) exhibits superior charge storage performance, with a specific capacitance of 355.8 F g−1 at 1 A g−1 and 220.8 F g−1 at high current density of 30 A g−1. Moreover, PAZ/PC electrode has more durable long-term charge-discharge stability (capacitance retention is 98 % after 10,000 charge and discharge cycles). The assembled symmetrical supercapacitor exhibits excellent energy-power characteristics (21.4 Wh kg−1 at 700 W kg−1) and durable cycle stability. This work sheds light on the design of stable organic electrode towards high-performance supercapacitor.

Regulating Zn Deposition Manner by Confining the Reactivity of Free Water in the Electric Double Layer.

Aqueous Zn ion batteries (AZIBs) are promising candidates of next-generation energy storage devices with high safety and theoretical capacity. However, the irreversibility of metallic Zn anode, attributed to dendrite growth and water decomposition, severely limits the cycling durability of AZIBs and restricts their further development. Herein, a facile surface engineering strategy is put forward to tackle the issue of poor reversibility of the Zn anode. Benzotriazole (BTA) is employed as a functional additive of ZnSO4 electrolyte to confine the reactivity of free water situated in the electric double layer (EDL). Experimental results and theoretical simulation reveal that BTA can preferiencially adsorb onto the Zn surface to uniform Zn2+ ion distribution and alleviate H2O-involved side reactions like hydrogen evolution, and surface passivation. Consequently, in BTA-modulated aqueous electrolyte, the lifespan of the Zn anode is extended from 170 h to 1092 h at 1 mA cm-2/1 mAh cm-2. The reversibility improvement of Zn anode also benefits the cycling durability of full devices including supercapacitors and batteries. Zn||I₂ batteries assembled in as-designed electrolyte witness only 11.3% capacity decay over 17000 cycles at 1 A g-1, far outstripping that observed in ZnSO4 counterpart (~ 4675 cycles).

Coupling (NixCo1-x)0.85Se with N-doped MoSe2 for hybrid supercapacitors with remarkable cyclic durability

Despite being a novel supercapacitive material, the widespread application of layered molybdenum diselenide has been hindered by its low specific capacity, significant volume changes during electrochemical reactions, and slow kinetics. In this study, we successfully combined (NixCo1-x)0.85Se nanoparticles with N-MoSe2 to create (NixCo1-x)0.85Se/N-MoSe2 hybrids (labeled as AxB1-xC). The electrochemical performance of AxB1-xC was dramatically improved due to the synergistic effects between nickel and cobalt, as well as between (NixCo1-x)0.85Se and N-MoSe2. Among the various AxB1-xC electrodes, the A0.8B0.2C electrode exhibited the best electrochemical performance when the Ni/Co ratio was 0.8/0.2. It provided a specific capacity of 397.9 C g−1 at 0.5 A g−1 and retained 220.0 C g−1 after 2,000 cycles at 10 A g−1. Furthermore, we constructed an A0.8B0.2C//AC hybrid supercapacitor to assess its energy storage capability. The A0.8B0.2C//AC device achieved a specific capacitance of 72.6 F g−1 at 0.5 A g−1 with an energy density of 25.8 Wh kg−1 at 400 W kg−1. The capacitive retention of the A0.8B0.2C//AC device was 92.9 % after 40,000 cycles at 3 A g−1. Impressively, a self-constructed A0.8B0.2C//AC device could power a timer for about 24 min, demonstrating its potential for practical applications.