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Plenty of metal sulfides have been employed as electrocatalysts to accelerate sluggish redox reaction kinetics and inhibit the annoying shuttle effect of lithium polysulfides (LiPSs) for lithium–sulfur (Li–S) batteries. Nevertheless, the activity of these catalysts is restricted by the limited number of active sites and poor electrical conductivity, resulting in disappointing cycling performance and rate stability. Herein, CoS2/MoS2 heterostructures anchored on carbon nanotubes (denoted as CoS2–MoS2/CNT) are fabricated by a facile hydrothermal method combined with a vulcanization process, and they serve as a multifunctional interlayer on a PP separator for Li–S batteries to solve the above problems. A series of systematic experiments and in situ spectroscopy elucidate that the interfacial interaction in the CoS2–MoS2 heterojunction not only activates Co sites in favor of anchoring LiPSs and inhibiting the shuttle effect but also synchronously induces the phase transformation of MoS2 from semi-conductive 2H to metallic 1T, and the ample yield of basal and edge defects contributes to the rapid catalytic kinetics of sulfur species. Consequently, a Li–S battery decorated with a CoS2–MoS2/CNT separator delivers a sparkling initial capacity of 921.8 mA h g−1 at 2C with a degradation rate of only 0.036% per cycle over 1000 cycles. This study provides novel insights for interfacial engineering and defect chemistry in durable Li–S electrochemistry and provides a prospective strategy for rational electrocatalyst designs with regard to the diverse energy-storage realm. [ABSTRACT FROM AUTHOR]

Conductive polymer composites (CPCs) with a positive temperature coefficient (PTC) have received considerable attention in the intelligent electric heating field due to their low cost, chemical stability, flexibility, and formability compared to conventional inorganic ceramic PTC composites. To fabricate high-performance PTC composites for application, considerable efforts have been made to improve the overall PTC performance of CPCs in both academia and industry. However, few reviews are focusing on the systematic summary and discussion regarding the research strategies to improve the PTC performance of CPCs. In this review, the conductive mechanism and PTC effect mechanism of CPCs with the PTC effect are first summarized. Then, the research strategies to regulate the PTC performance of CPCs are systematically reviewed in terms of the polymer matrix, conductive fillers, and preparation processes. CPCs with a crystalline polymer and an amorphous polymer as the matrix are reviewed separately, especially for the former due to their current widespread application in PTC composites. Meanwhile, the various research strategies for improving the PTC performance are analyzed and summarized. The current challenges and future outlook in this field are also discussed. The research strategies reviewed here for improving the PTC performance of CPCs can provide a comprehensive guide for researchers seeking high-performance PTC composites. [ABSTRACT FROM AUTHOR]

The search for earth abundant, highly active, and robust electrocatalysts is central to the wide spread application of renewable energy conversion technologies. Herein, bulk nitrogen-doped hierarchical structure cobalt carbide, which was composed of nano/micro-particles and coupled with carbon black (denoted as N-Co2C HS/EC), was developed as a bifunctional oxygen electrocatalyst. N-Co2C HS/EC exhibited a high half-wave potential of 0.825 V for the oxygen reduction reaction and a low overpotential of 287 mV for the oxygen evolution reaction, both of which were superior to those of precious Pt/C and RuO2 catalysts. Impressively, a rechargeable zinc–air battery driven by bifunctional N-Co2C HS/EC delivered a larger peak power density (205 mW cm−2), a higher specific capacity (793.08 mW h gZn−1), and better rate performance than the one driven by Pt/C + RuO2 mixture catalysts. Systematic characterization studies and theoretical calculations revealed that the enhanced oxygen electrocatalysis of N-Co2C HS/EC was attributed to the increased amount of active Co–Nx moieties and the tailored electronic structure due to nitrogen doping. Moreover, the integrated microrod/sheet array benefited the electrocatalytic stability and electron/mass transmission. This work proposed an in situ nitrogen-doping strategy to substantially boost the electrocatalytic performance of metal carbides, which may inspire more effort for developing efficient metal compound electrocatalysts for energy conversion. [ABSTRACT FROM AUTHOR]

Zinc sulfide (ZnS) is considered as a candidate anode material to replace commercial graphite anodes in high-performance lithium-ion batteries (LIBs). However, the significant volume change during the lithiation/delithiation process leads to poor cycle and rate performance, severely limiting the application of the ZnS anode in LIBs. Here, core–shell ZnS@C microrods (ZnS@C MRs) were synthesized via a simple hydrothermal method, followed by in situ polymerization and a sulfidation process. Due to the rationally designed structure, the outer carbon shell can avoid the volume expansion of ZnS, thus maintaining the structural stability. Moreover, the carbon shell can not only enhance the conductivity, but also inhibit direct contact between ZnS and the electrolyte during the repeated lithiation/delithiation process. Accordingly, ZnS@C MRs exhibit outstanding electrochemical performance in LIBs. Specifically, a capacity of 392 mA h g−1 is obtained after 500 cycles at 1.0 A g−1. Moreover, a capacity of 162 mA h g−1 is maintained at 3.0 A g−1. [ABSTRACT FROM AUTHOR]

Elimination of interfacial thermal resistance is a critical issue to improve the thermal conductivity of graphene-based metal matrix composites. Here, thiophenol groups were employed to construct an interfacial molecular junction between graphene and copper to improve the thermal conduction performance of the graphene/copper composite. The highly delocalized aryl properties of thiophenol groups can facilitate electron tunneling at the interface, thereby increasing the electron thermal conduction and reducing the interfacial thermal resistance between graphene and copper nanoparticles. The resulting thiophenol group linked graphene and copper composite shows a high thermal conductivity of 500.6 W m−1 K−1, which is 1.43 and 1.30 times higher than those of copper (Cu) and pristine graphene–copper composites (Gr–Cu), respectively, and also higher than most reported values via a single phonon thermal conduction route. Placed on a heat source heated from 26 °C to 213 °C within 5 min, the top surface temperature of TP–Gr–Cu increases to 184.2 °C rapidly, whereas those of Gr–Cu and Cu only increase slowly to 61.4 °C and 51.6 °C. This work demonstrates that an interfacial electron thermal conduction route can be built through electron tunneling by constructing a molecular junction between graphene and copper, which can significantly reduce the interfacial thermal resistance and improve the interfacial thermal conductivity. [ABSTRACT FROM AUTHOR]

Lithium iron phosphate (LFP) has become one of the current mainstream cathode materials due to its high safety and low price. Most modification methods applied (e.g. ion doping, carbon coating and particle size restriction) are used to overcome its poor electronic and ionic conductivity. Here, the Y–F co-doped LFP/carbon (LFP/C) precursor was successfully synthesized using a high temperature solid phase method. The electronic conductivity of the material is enhanced by doping with F which induces the rearrangement of the PO43+ electron cloud, while the doping with Y introduces Li+ vacancies, thereby reducing the space resistance of Li ion diffusion, resulting in an overall enhancement of the ionic conductivity of the material. In addition, XRD refinement results show that Y and F doping leads to a weakening of the Li–O bond while also widening the lithium ion diffusion tunnel, thereby increasing the lithium ion diffusion rate. Therefore, this work has produced LFP/C-YF-2, which exhibits an ultra-high discharge specific capacity of 135.8 mAh g−1 at 10C, and a discharge specific capacity of 148.6 mA h g−1 without attenuation after 700 cycles at 5C. It is hoped that this high-capacity and high-rate cycling stability material will become a promising cathode material for applications in high-power electric vehicles and other equipment. [ABSTRACT FROM AUTHOR]

Tin sulfide (SnS) has attracted much attention as an anode material for sodium ion batteries (SIBs) because of its various advantages, including high capacity and unique 2D structure. However, SnS has poor electrochemical performance caused by the large volume change and low intrinsic electric conductivity, which seriously limited its practical application in SIBs. Herein, we successfully constructed bimetallic sulfide SnS/MoS2 heterostructures decorating N, S co-doped carbon nanosheets (SnS/MoS2/NS-CNs) as anode materials for SIBs. The designed SnS/MoS2 heterostructures induce an electric field within the nanocrystals, which lead to lower ion-diffusion resistance and facilitate interfacial electron transport. Moreover, the N, S co-doped carbon nanosheets can buffer the volume change of SnS/MoS2, avoiding the direct contract between SnS/MoS2 and electrolyte, as well as favorable transport kinetics for electrons and ions. Accordingly, benefiting from these merits, the as-prepared SnS/MoS2/NS-CNs exhibit outstanding rate capability (372.9 mA h g−1 at 5.0 A g−1) and long-term cycling performance (287.2 mA h g−1 after 800 cycles at 1.0 A g−1). [ABSTRACT FROM AUTHOR]

The nickel-rich layered material LiNi0.8Co0.1Mn0.1O2 (NCM) is a promising candidate cathode material for next generation lithium-ion batteries due to its high energy density and relatively low cost. Unfortunately, NCM suffers from capacity fading upon cycling and poor rate capability that seriously limit its wide application. To overcome these drawbacks, we present an effective inorganic coating strategy for a complex LixNi1−yFeyO2&NiFe2O4 (LNFO&NFO) in situ surface modified NCM cathode material by a sample wet-chemical method, which could effectively stabilize the layer structure and eliminate lithium impurities. As a result, LNFO&NFO surface modified NCM shows excellent electrochemical performance. For example, the optimized NFO-2 cathode not only shows an excellent rate performance with a discharge capacity of 140.56 mA h g−1 at 10C, but also exhibits outstanding cycling stability with an improved capacity retention of 87.43% and 74.32% at 1C after 250 and 100 cycles at room and elevated temperatures of 25 and 55 °C. The superior electrochemical performance is attributed to the dual functions of NiFe2O4 modification. The formed LNFO&NFO coating layer bonds with the surface oxygen vacancies of the bulk material which could effectively stabilize the surface structure and bulk structure associated with capacity degradation as well as the electrical and ionic conductivity at the interface. Therefore, ingenious design of the LNFO&NFO surface coating layer is a key approach for improving the durability of the NCM cathode material during the cycling process. [ABSTRACT FROM AUTHOR]

Si has received much attention as an anode material for high performance LIBs due to its high theoretical capacity. Nevertheless, the serious volume changes during the lithiation/delitaiation process and poor electrical conductivity result in fast capacitative decay and poor rate performance, which seriously limit its practical applications. Herein, a 2D Si@graphitic carbon (GC) nanosheets composite was synthesized through the facile ball-milling method using NaCl as a bifunctional template, which not only served as a hard template but also stabilized the Si nanoparticles during the fabrication process. In this rationally designed architecture, Si nanoparticles are embedded into carbon nanosheets and encapsulated by a graphitic carbon wall. Therefore, the 2D Si@GC nanosheets composite as an anode for LIBs with outstanding cycling and rate performance, delivered a high capacity of 1450.7 mA h g−1 after 400 cycles at 0.5 A g−1, and maintained high reversible capacity of 877.4 mA h g−1 even at 3.0 A g−1. This outstanding electrochemical performance can be ascribed to the carbon nanosheets effectively buffering the volume change of the Si nanoparticles, graphitic carbon wall improving the electrical conductivity and 2D nanosheets facilitating the transport of Li+ during the charge/discharge process. Thus, the Si@GC nanosheet composite exhibited an outstanding rate and cycling performance. [ABSTRACT FROM AUTHOR]

Electrochemical reduction of carbon dioxide (ERCO2) to low-carbon fuel and useful chemicals, which can simultaneously store renewable energy and recover CO2 in a green manner, has proven to be a viable energy storage and conversion strategy. However, there is always a technical bottleneck in preparation of highly active, selective and stable catalysts. In this work, we hydrothermally synthesized a new type of bismuth-based organic framework (Bi–MOF) and carefully investigated it as the catalyst for ERCO2. All the samples exhibited excellent performance and the optimized one (i.e. Bi-BTC-D) achieved a high formate Faraday efficiency (FE) up to 95.5% at −0.86 VRHE and a current density of −11.2 mA cm−2. Moreover, the FE has been maintained over 90.0% after 12 hours of continuous electrolysis without significant reduction. The measurement results demonstrated that the excellent performance can be attributed to the special structure of Bi-BTC-D. DFT calculations show that the Bi site of Bi-BTC-D is highly efficient for formate production with very low overpotentials. The great potential of using a Bi–MOF as a highly stable, molecularly tunable catalytic material for ERCO2 is confirmed. [ABSTRACT FROM AUTHOR]

A Sn/SnOx/MoS2/C composite material with superior performance was developed as an anode for lithium-ion batteries via a facile and scalable ball-milling method using a three-dimensional (3D) self-assembly of NaCl particles as a template. In the constructed architecture, carbon nanosheets avoided the direct exposure of encapsulated Sn/SnOx nanoparticles to the electrolyte and preserved the structural and interfacial stability of the nanoparticles, protecting them from volume expansion during the charge/discharge process. The MoS2 particles, uniformly dispersed on the carbon nanosheets, facilitate an efficient ion transport and ensure structural durability as a particle reinforcing agent. When used as an anode material in lithium-ion batteries, the as-prepared Sn/SnOx/MoS2/C composite exhibit a high rate performance and long cyclic stability, even at a high current density of 3 A g−1 (specific capacity of 725.3 mA h g−1 after 800 cycles). This simple fabrication method and the excellent electrochemical performance demonstrates the potential use of the Sn/SnOx/MoS2/C composite as an anode material for high-performance lithium-ion batteries. [ABSTRACT FROM AUTHOR]

A new type of Sn@SnO2@C@MoS2 composite, composed of Sn@SnO2@C nanosheets and decorated with MoS2, exhibits significantly improved electrochemical performance. This composite has excellent long-term cycling stability (841 mA h g−1 at 1.0 A g−1 after 400 cycles) and superior high-rate capability (458.3 mA h g−1 at 10.0 A g−1) due to the strong synergistic effect between the MoS2 and Sn@C nanosheets. [ABSTRACT FROM AUTHOR]

A facile strategy for preparing a novel Sn/MoS2/C composite has been developed via a simple hydrothermal route and then annealing in an Ar atmosphere. The synthesis of layer-structured MoS2 and amorphous carbon can effectively restrict the volume change of Sn during the charge and discharge process. The Sn/MoS2/C composite was evaluated as an anode material for lithium-ion batteries, and exhibits a stable and high reversible capacity of 707 mA h g−1 at 500 mA g−1 after 100 cycles. The significantly improved Li ion storage and stable capability are attributed to the layer-structured MoS2 nanosheets and the amorphous carbon coated layer, which alleviate the large volume changes of Sn and enhance the electron and Li ion diffusion transport in the composite. [ABSTRACT FROM AUTHOR]

The goal of this research was to study the effect of molecular structure surfactant on the performance of LiFePO4/C composite. The solid state reaction method was applied to prepare a series of LiFePO4/C materials by adding various surfactants. The materials were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Infrared spectrum analysis (FTIR), Raman spectral analysis and electrochemical methods. The results confirm the existence of interactions between the surfactant molecules and the precursor that contribute to the formation of nanoparticles and a homogeneous carbon coating layer on the surface. The structure of the surfactants played an important role in improving the performance of LiFePO4/C composites. The structures of surfactants affect the particle size and the amount of graphite-like carbons of LiFePO4/C composites. The surfactant with longer alkyl C–C chain length could effectively prevent particle growth, while the surfactant with shorter alkyl C–C chain length form more graphene-like carbon during pyrolysis. The as-prepared LiFePO4/C particles using various surfactants show different electrochemical performances. According to Raman spectroscopy and EIS analysis, these composites have different ID/IG peak ratios and charge transfer resistance. Especially, LiFePO4/C synthesis with composite surfactant (weight ratio of Tween80 to Tween20 equal to 1.5) showed an excellent electrochemical performance with a discharge capacity of 167.3 mA h g−1 at 0.1 C rate and 129.4 mA h g−1 at 5 C rate. [ABSTRACT FROM AUTHOR]

A new class of micro/nano composite architecture, characterized by radially grown MnO2nanoneedles on high specific surface area (SSA) mesoporous carbon microspheres (MCMs), is presented for the first time as electrode materials for electrochemical capacitors (ECs). This unique architecture could be considered as an omnibearing oriented 1-D nanostructure which possesses high power features for EC applications. When evaluated for electrochemical capacitance performance in a non-aqueous electrolyte, this composite architecture demonstrates improved electrochemical properties with maximum specific energy and energy density of 164 W h kg−1and 25 kW h L−1, respectively. This enhanced performance could be mainly attributed to the integration of efficient double layer capacitance and tremendous pseudo-capacitance from MCMs and MnO2. Our findings suggest that this composite architecture might be used as a promising anode material for high performance ECs. [ABSTRACT FROM AUTHOR]

Layered graphene and molybdenum disulfide have outstanding sodium ion storage properties that make them suitable for sodium-ion batteries (SIBs). However, the easy and large-scale preparation of graphene and molybdenum disulfide composites with structural stability and excellent performance face enormous challenges. In this study, a self-supporting network-structured MoS 2 /heteroatom-doped graphene (MoS 2 /NSGs-G) composite is prepared by a simple and exercisable electrochemical exfoliation followed by a hydrothermal route. In the composite, layered MoS 2 nanosheets and heteroatom-doped graphene nanosheets are intertwined with each other into self-supporting network architecture, which could hold back the aggregation of MoS 2 and graphene effectively. Moreover, the composite possesses enlarged interlayer spacing of graphene and MoS 2 , which could contribute to an increase in the reaction sites and ion transport of the composite. Owing to these advantageous structural characteristics and the heteroatomic co-doping of nitrogen and sulfur, MoS 2 /NSGs-G demonstrates greatly reversible sodium storage capacity. The measurements revealed that the reversible cycle capacity was 443.9 mA h g -1 after 250 cycles at 0.5 A g -1 , and the rate capacity was 491.5, 490.5, 453.9, 418.1, 383.8, 333.1, and 294.4 mA h g -1 at 0.1, 0.2, 0.5, 1, 2, 5 and 10 A g -1 , respectively. Furthermore, the MoS 2 /NSGs-G sample displayed lower resistance, dominant pseudocapacitive contribution, and faster sodium ion interface kinetics characteristic. Therefore, this study provides an operable strategy to obtain high-performance anode materials, and MoS 2 /NSGs-G with favorable structure and excellent cycle stability has great application potential for SIBs., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

Rational interface control of porous carbon electrode materials is of significance for achieving efficient supercapacitors. Herein, biomass-derived carbon microspheres with a highly graphitized porous surface and amorphous subsurface were well constructed via a flexible coupled catalysis-activation process. The unique structure not only endows the carbon microspheres with rapid electron transfer but also an ultra-high specific surface area. Owing to the optimized graphitized/amorphous structure, the obtained graphitized and activated starch-derived carbon microspheres display obviously impressive energy storage capability among the reported starch-derived carbon materials, even though they were evaluated in a narrow voltage window. The assembled symmetrical supercapacitor based on the optimized carbon microspheres exhibits a high capacitance of 198 F g -1 at 1 A g -1 , a high energy density of 14.67 W h kg -1 at a power density of 4142.80 W kg -1 , robust cycle performance, and good rate performance in alkaline aqueous electrolyte. This work provides a strategy for flexible construction of biomass-derived carbon electrode materials, with an optimized graphitized/amorphous and porous structure, for boosted energy storage in supercapacitor applications., Competing Interests: The authors declare no conflict of interest., (This journal is © The Royal Society of Chemistry.)

Biomass waste recycling and utilization is of great significance for improving ecological environments and relieving the current energy crisis. Waste diatomite with an adsorbed mass of yeast protein resulting from beer filtration is feasibly converted into N-doped porous carbon (NPC) via high temperature thermal treatment. The resulting NPC inherits the three-dimensional hierarchical structure of the diatomite, with a unique rich-pore feature composed of micro/meso/macropores, which is beneficial for high exposure of the electrocatalytic sites and ion transfer and diffusion. The NPC compounds with controllable nitrogen doping are used for the oxygen reduction reaction (ORR) and in a supercapacitor. NPC-2 exhibits a half-wave potential of 0.801 V comparable to that (0.812 V) of commercially available Pt/C in alkaline media, along with a good methanol tolerance capacity and long-term stability for the ORR. Furthermore, as an electrode material, a symmetric supercapacitor based on NPC-2 manifests an outstanding specific capacitance of 151.5 F g -1 at a current density of 1 A g -1 and a considerable capacitance retention of 90.5% after a cycling performance test of 10 000 cycles. The NPC-2 based symmetric SC delivered an energy density of 13.47 W h kg -1 at a power density of 400 W kg -1 . This work highlights the environmental significance of converting waste diatomite into metal-free ORR catalysts and electrode materials for energy conversion and storage technologies., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

Numerous efforts have been devoted to capability improvement and cycling stability in the past decades, and these performances have been significantly enhanced. Low initial coulombic efficiency is still a problem in the metal sulfide-based anode materials. This study developed a strategy to achieve high initial coulombic efficiency and superior capacity retention by interpenetrating binary metal sulfides of SnS and MoS 2 in a conductive carbon matrix. The synergy ascension of electrochemical performances for the metal sulfides is attributed to their mutual impeding effects on coarsening of metal grains and the capsule-shaped coating structure embedded in the carbon sheet architecture. The SnS/MoS 2 /C composite was prepared by a simple NaCl template-assisted ball milling method, and showed excellent electrochemical performances in terms of a high initial coulombic efficiency up to 90.2% and highly stable reversibility with a specific capacity of 515.4 mA h g -1 after 300 cycles at 1.0 A g -1 . All of these characteristics suggest that the proposed materials are superior among the previously reported metal sulfide-based anode materials for lithium-ion batteries., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

Selectively creating active sites that can work well in different media as much as possible remains an open challenge for the widespread application of sustainable metal air batteries and fuel cells. Herein, short-range amorphous nitrogen-doped carbon nanosheets (NCS) coupled with partially graphitized porous carbon architecture were reported, and were prepared via flexible salt-assisted calcination strategy and followed by a simple cleaning process. The short-range amorphous structure not only significantly promotes the exposure of electrochemically active sites of carbon defects with less protonation in acidic medium, but also maintains the structural stability and electron conduction of the NCS. This unique structure endows the NCS (0.832 V) with efficient ORR electrocatalytic performance with a high half-wave potential ( E 1/2 ) comparable to that of commercial Pt/C (0.837 V) in alkaline electrolyte and an impressive E 1/2 of 0.64 V in harsh acidic medium, making it outstanding among the reported analogous metal-free carbon electrocatalysts. In addition, the NCS manifests robust stability for ORR electrocatalysis with little change in the catalytic activity after accelerated stability tests. This work will provide a feasible inspiration to the construction of carbon nanomaterials with high active site density for efficient energy conversion-related electrochemical reactions., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

Water-soluble AgInZnS quantum dots (AIZS QDs) were synthesized with glutathione (GSH) as a stabilizer by a facile one-step method based on a hydrothermal reaction between the nitrate salts of the corresponding metals and sodium sulfide as a sulfide precursor at 110 °C. The optimal reaction conditions (temperature, time, pH, and the molar ratios of the precursors) were studied. According to the data from TEM, XPS, and XRD, AIZS QDs were characterized with excellent optical properties. The results showed that the aqueous-dispersible AIZS QDs were quasi-spherical and their average diameter was 3.51 nm. Furthermore, the cytotoxicity of AIZS QDs was investigated by microcalorimetry and microscopy techniques (confocal microscopy and TEM). The data revealed that AIZS QDs exhibited low toxicity, biocompatibility, and good water stability, due to which they could be used as a fluorescent probe for bioimaging and labeling. In addition, AIZS QDs could be used as a sensor to detect Cu 2+ because the fluorescence of AIZS QDs was quenched by Cu 2+ ., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

The oxygen evolution reaction (OER) is an important reaction especially in water splitting and metal-air batteries. Highly efficient non-noble metal based electrocatalysts are urgently required to be developed and to replace the commercial Ru/Ir based oxide. Herein, we report the three-dimensional hierarchical NiCo 2 O 4 /CNT-150 composite with high activity for the OER that was synthesized via a hydrothermal reaction and subsequent annealing. Compared with CNTs, commercial RuO 2 catalysts, NiCo 2 O 4 /CNT, NiCo 2 O 4 /CNT-250, and NiCo 2 O 4 /CNT-150 exhibit enhanced electrocatalytic performance with a lower onset overpotential of 300 mV and the corresponding Tafel slope of 129 mV per decade. The flower-like NiCo 2 O 4 /CNT-150 shows an excellent catalysis performance with higher current density than the commercial RuO 2 catalyst. Moreover, the NiCo 2 O 4 /CNT-150 demonstrates the excellent long-term durability in 0.1 mol L -1 KOH for the OER. The significant catalytic performances are ascribed to the excellent conductivity of CNTs and the high specific surface area of the three dimensional flower-like NiCo 2 O 4 ., Competing Interests: This work has not been published previously. It is not under consideration for publication elsewhere, and its publication is approved by all authors and tacitly or explicitly by the responsible authorities where the work was carried out. If accepted, it will not be published elsewhere in the same form, in English or in any other language, without the written consent of the Publisher., (This journal is © The Royal Society of Chemistry.)