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Developing low-cost and highly efficient electrode is essential for energy storage and conversion device. Herein, CoNi hydroxide nanosheets functionalized by borate ions (denoted as CoNiB) are fabricated via a convenient wet chemical process and subsequent hydrothermal boronization reaction. It is observed that rapid generation of hydrogen in the boronization process favors the formation of nanosheets. Moreover, hydrogen as a gas template is conductive to the formation of 3D loose porous structure which not only facilitates electrolyte penetration, but also exposes more active sites and accelerates the transport of ions and electrons. Resulting from the unique hierarchical microstructure, the optimized CoNi(1:1)B electrode delivers a high specific capacity of 283.25 mAh/g at 1 A g−1 as well as good rate capability (259.38 mAh/g at 20 A g−1) and stability. Besides, the assembled asymmetric supercapacitor (ASC) device with CoNi(1:1)B as positive electrode and activated carbon as negative electrode displays an outstanding energy density of 64.7 Wh kg−1 at 814.7 W·kg−1 with good cyclability (93 % after 15,000 cycles), verifying the great application potential of CoNi(1:1)B in practice. [Display omitted] • CoNiB nanosheets were fabricated by a facile two-step method. • The rate of hydrogen produced during boronization process would affect the morphology of the electrode. • The mesoporous structure of CoNiB enables high exposure of active sites and fast transport of ions and electrons. • BO 2 − functionalized CoNi hydroxides strengthens the electrochemical performance. • The assembled hybrid supercapactor exhibits excellent supercapacitor performance. [ABSTRACT FROM AUTHOR]

The dependence of the structure of (TiZrHf)N coatings deposited by reactive magnetron sputtering on different working pressures and their mechanical and electro-optical properties were investigated. The increased working pressure contributed to the decreased oxygen contamination. With increased working pressure, the compressive stress was transitioned to tensile one. Compressively stressed coatings consisted of tightly packed columns with a smooth surface. The tensile stressed coatings presented void network structure surrounding the columnar grains with a rough surface. Moreover, the grain size initially increased and subsequently decreased. Accordingly, the (TiZrHf)N coatings deposited at high working pressure were characterized with poor hardness, low electrical conductivity, and low light reflectivity due to the porous structure and high oxygen contamination. In addition, the coating color changed from bright gold to dark gray. In this study, the working pressure was proven a sensitive deposition parameter in controlling the microstructure, mechanical, and electro-optical properties of the coating. The wide structural variation in the (TiZrHf)N coatings allowed a diverse physical performance suitable for a broad range of applications. [ABSTRACT FROM AUTHOR]

Indium zinc oxide (IZO) films were grown by direct current magnetron sputtering from vacuum hot-pressed ceramic oxide targets of In 2 O 3 :ZnO with a weight ratio of 7:3 onto glass substrates. No external heating of the substrate was used during deposition. The thickness dependences of the structural, optical, and electrical properties of IZO films were characterized. The IZO film structure remained amorphous with low roughness as its thickness increased but showed an increased degree of short-range order. The thick IZO film contained relatively high carrier concentration and mobility but exhibited low transmittance in the visible region and high reflectance in the IR region. The smallest electrical resistivity was 5.44 × 10 −4 Ω-cm for the 800 nm-thick IZO film. The optical band gap shifted to a higher energy with thickness as the carrier concentration and Urbach energy increased. An inverse linear relation was found between band gap energy and Urbach energy. In consideration of the figure of merit values, the optimized thickness of the IZO film was 800 nm due to the effect of IZO film thickness on sheet resistance. Given its low temperature process and good optoelectronic properties, the IZO film has a wide range of potential applications in various optoelectronic devices. [ABSTRACT FROM AUTHOR]

The exploration of high-efficiency electrodes is urgent for energy conversion and storage devices. In this work, CoNiBP nanosheets were fabricated by a successive method which is facile and cost-effective. The nanosheet-like structure of CoNiBP enables high exposure of active sites and fast transport of ions and electrons. In addition, the synergistic effect of B and P strengthens the electrochemical performance by tuning the electronic structure of active sites. The CoNiBP electrode exhibits a high specific capacity of 870.8 C g−1 at 1 A g−1 with excellent rate capability and stability. Moreover, the assembled CoNiBP//AC asymmetric supercapacitor (ASC) device delivered an ultrahigh energy density of 71.7 Wh kg−1 at 0.8 kW·kg−1 with good cyclability (∼100% retention of original capacity after 12 000 cycles). With such superior electrochemical performance, CoNiBP is a promising material to be used as electrode in supercapacitors. [Display omitted] • CoNiBP nanosheets were fabricated by a successive facile and low-cost method. • The sequence of boranation and phosphation process affects the morphology and active sites. • The synergistic effect of B and P strengthens the electrochemical performance. • The assembled hybrid supercapactor exhibits excellent supercapacitor performance. [ABSTRACT FROM AUTHOR]

The exploration of high-efficiency electrodes is urgent for energy conversion and storage devices. In this work, CoNiBP nanosheets were fabricated by a successive method which is facile and cost-effective. The nanosheet-like structure of CoNiBP enables high exposure of active sites and fast transport of ions and electrons. In addition, the synergistic effect of B and P strengthens the electrochemical performance by tuning the electronic structure of active sites. The CoNiBP electrode exhibits a high specific capacity of 870.8 C g−1 at 1 A g−1 with excellent rate capability and stability. Moreover, the assembled CoNiBP//AC asymmetric supercapacitor (ASC) device delivered an ultrahigh energy density of 71.7 Wh kg−1 at 0.8 kW·kg−1 with good cyclability (∼100% retention of original capacity after 12 000 cycles). With such superior electrochemical performance, CoNiBP is a promising material to be used as electrode in supercapacitors. [Display omitted] • CoNiBP nanosheets were fabricated by a successive facile and low-cost method. • The sequence of boranation and phosphation process affects the morphology and active sites. • The synergistic effect of B and P strengthens the electrochemical performance. • The assembled hybrid supercapactor exhibits excellent supercapacitor performance. [ABSTRACT FROM AUTHOR]

Various (AlCrMoTaTi)-Si x -N coatings were prepared on Si substrates through a reactive magnetron sputtering system to methodically investigate the effects of Si contents and free Si on oxidation behavior. The as-deposited Si-containing coating presented a relatively dense and compact structure compared with the Si-free coating. An oxide layer was formed on the coating surface and continued to thicken when the coatings were exposed to ambient air at elevated temperatures. At 1073 K, a two-layer structure, which consists of an amorphous Al 2 O 3 layer with traces of other target elements followed by a rutile TiO 2 + oxide of the target element mixed zone, was developed in the oxide layer. Oxidation resistance was gradually enhanced with the continued increase in Si concentration in the coatings. At 1173 K, the coatings with Si content of as low as 7.51 at.% exhibited a single order of magnitude lower oxidation rate than that of the Si-free coating. Nanohardness measurement of the coatings further confirmed the oxidation behavior. The significantly enhanced oxidation resistance may be attributed to the presence of Al and Si in the coatings. [ABSTRACT FROM AUTHOR]

This study aimed to investigate the effects of discharge power on the composition and the microstructural, mechanical, and electro-optical properties of (TiZrHf)N coatings. The coatings were deposited on Si substrates via reactive magnetron sputtering. The coatings were deposited at varying discharge powers (50–300 W). At low discharge powers, amorphous structures were produced during the initial sputtering period. High (2 0 0)-axis orientation structures were formed when sputtering time was increased. The upper part of the coatings was composed of open columnar structures with extended voids along the column boundaries. Increasing the discharge power decreased the thickness of the amorphous layer. Consequently, the microstructures became dense and compact; however, the grain size did not change significantly. Meanwhile, an enhanced compressive stress was observed, followed by an increase in the texture coefficients of the (1 1 1) plane and lattice parameters. The physical properties of the coatings were improved by increasing the discharge power. The coating hardness was increased to approximately 32.1 GPa. In addition, the electrical resistivity was decreased to approximately 134 μΩ cm, and the light reflectivity in the infrared region (700–2400 nm) was increased to 75%. [ABSTRACT FROM AUTHOR]

Si-doped (AlCrMoTaTi)N coatings were deposited onto an Si substrate by radio-frequency magnetron sputtering of an AlCrMoTaTi alloy target under direct current bias in an N 2 /Ar atmosphere. The crystal, microstructural, mechanical, and electrical properties at different Si-target powers were investigated. As the Si content reached 7.51 at.%, the simple NaCl-type face-centered cubic structure of nitride was retained. Significant lattice decline and grain growth were observed in the nitride coatings. The microstructure of coatings transformed from loose columns with rough-faceted surface into dense ones with smooth-domed surface. The solubility of approximately 7.51 at.% Si content was demonstrated. Si incorporation significantly improved the mechanical properties of the coatings, but degraded their electrical properties. The hardness of the coatings increased from 20.7 GPa to 35.5 GPa, and the electrical resistivity increased from 793 μΩ cm to 3872 μΩ cm. [ABSTRACT FROM AUTHOR]

Abstract: The (TiVCr)N coatings were deposited on Si substrate via rf magnetron sputtering of a TiVCr alloy target under dc bias in a N2/Ar atmosphere. The deposition rate of the coatings gradually decreased with increasing N2-to-total (N2 +Ar) flow ratio, R N. The TiVCr alloy and its nitride coatings exhibited a body-centered cubic (BCC) and a face-centered cubic (FCC) crystal structure, respectively. The preferred orientation of the (TiVCr)N coatings changed from (111) to (200) with increasing R N. In addition, the microstructure of the nitride coatings was also converted from a columnar structure with void boundaries and rough-faceted surface to a very dense structure with a smooth-domed surface. The grain size of the (TiVCr)N coatings decreased as the R N was increased. Accordingly, the hardness of the (TiVCr)N coatings was enhanced from 4.06 to 18.74GPa as the R N was increased. [ABSTRACT FROM AUTHOR]

The electroactivity and cyclic stability of transition metal phosphides (TMPs) for supercapacitors are restricted by inadequate redox active sites and huge volume changes during the charging/discharging process. Herein, a three-dimensional (3D) porous Ni 2 P/NiMo-layered double hydroxide (NiMo-LDH) heterostructure with large specific surface and abundant pore channels is explored as a self-supporting supercapacitor electrode. The well-defined hierarchical pore structure can offer numerous electroactive sites and short ion/electron pathways. The generation of heterointerfaces between multi-dimensional Ni 2 P and two-dimensional (2D) NiMo-LDH nanosheets endows the hybrid composite with improved electrical conductivity and structural robustness. Consequently, the special nanoarchitecture design achieves a specific capacity of 198.6 mAh g−1 (2.28 mAh cm−2) at 1 A g−1 and an impressive rate performance of 78.3% at 20 A g−1. More importantly, the assembled Ni 2 P/NiMo-LDH//orange peel-derived porous carbon (OPC) asymmetric supercapacitor (ASC) device delivers a remarkable specific energy of 63.7 Wh kg−1 at a specific power of 1138.3 W kg−1 and long-term cycling stability (91.7% over 10,000 cycles). The research highlights that the hybridization of TMPs and other nanostructured battery-type materials may produce a synergistic effect and boost the capacitive properties. [Display omitted] • 3D porous Ni 2 P/NiMo-LDH heterostructure is constructed. • A combination of Ni 2 P and NiMo-LDH can conquer their shortcomings. • The synergistic effect leads to boosted electrochemical behaviors. • Asymmetric supercapacitor illustrates an energy of 63.7 Wh kg−1/0.95 Wh cm−2. [ABSTRACT FROM AUTHOR]

Construction of ordered mesoporous carbon (OMC) with two-dimensional morphology and rich redox functionalities may offer the possibility for improving the supercapacitive performances of the OMC-based electrode materials in capacity and rate performance. Herein, a simple approach by assembly soluble phenolic resin with surfactant of F127 on a self-made magnesium hydroxide was developed and applied to the fabrication of ordered mesoporous carbon nanosheet (OMCN). The obtained OMCN possesses weak ordered mesoporous structure, nanosheet morphology, large surface area (1376 m2/g vs soft-templated OMC of 522 m2/g), rich cracks and abundant electroactive oxygen functionalities (13.6%). As electrode for supercapacitor, the OMCN exhibits a two times larger capacity than that of OMC (301 F/g vs 151 F/g) and excellent rate performance with capacitance retention of 84% (vs that of OMC of 62%). For aqueous symmetric supercapacitor in 1.0 M Na 2 SO 4 , the OMCN based electrode achieves an ultrahigh energy density of 25.3 Wh/kg at power density of 2000 W/kg. As cathode material working on the voltage range of 1.5–4.5 V, OMCN also exhibits a superior surface-driven lithium-ion storage performance including large capacity of 140 mAh/g at 0.5 A/g (vs that of OMC of 7.6 mAh/g), good rate performance and long cycle stability with about 96% capacity retention after 2000 cycles at 2A/g, showing a promising candidate for the electrochemical energy storage. Image 1 • Ordered mesoporous carbon nanosheet (OMCN) was simply fabricated. • OMCN owns larger surface area than F127 templated OMC (1375 vs 522 m2/g). • OMCN achieves larger capacity and higher capacitance retention than that of OMC. • OMCN exhibits superior surface-driven lithium-ion storage performance. [ABSTRACT FROM AUTHOR]

Abstract Biomass-derived porous carbon materials hold good prospects for application in supercapacitor owing to their natural abundance, low cost, as well as high heteroatoms content. Herein, multi-heteroatom-doped hierarchical porous carbon was prepared via on-step carbonization process by using chestnut shells as raw material and melamine as activation agent. The obtained chestnut shell-derived carbons exhibit a high specific area (691.8 m2 g−1), abundant interconnected micropores/mesopores, proper level of graphitization, considerable content of heteroatoms (∼3.79 at. % N, ∼13.35 at. % O, and ∼0.52 at. % S). Benefiting from these superior characteristics, the obtained carbon electrode exhibits a high specific capacitance (402.8 F g−1 at 0.5 A g−1 in a three-electrode system) and outstanding rate capability (45.3% capacitance retention at 100 A g−1) in KOH electrolyte. The fabricated symmetric supercapacitor delivers a superior energy density of 26.6 Wh kg−1 at a power density of 445.5 W kg−1. In addition, the supercapacitor device shows good cycling stability with a 96.6% capacitance retention after 20,000 cycles. These results demonstrates that the as-prepared carbonaceous materials have great potential for low-cost and high-performance supercapacitors. Graphical abstract Image 1 Highlights • A multi-heteroatom-doped porous carbon is prepared by one-step carbonization of mixtures of chestnut shells and melamine. • The hierarchical carbon electrode exhibits a high specific capacitance and excellent rate capability. • The assembled symmetric supercapacitor delivers a high energy density and superior cycling stability. [ABSTRACT FROM AUTHOR]

The performance of hybrid supercapacitors is restricted by inferior matched electrochemical kinetics of cathode and anode materials, leading to unsatisfactory energy density and poor cyclic stability. Herein, hierarchically porous cobalt iron selenide (Co 0.7 Fe 0.3 Se 2) @ nickel cobalt phosphate (NiCoPO) nanosheet arrays are successfully fabricated on carbon cloth substrate via an electrodeposition method, a hydrothermal treatment, followed by an electrodeposition process. The well-designed Co 0.7 Fe 0.3 Se 2 @NiCoPO cathode material not only combines the merits of high electrical conductivity of Co 0.7 Fe 0.3 Se 2 and high electrochemical activity of NiCoPO, but also generates interaction and synergistic effect between two constituents. Profiting from its unique core-shell heterostructure with short ion transfer roadways and enhanced conductivity, Co 0.7 Fe 0.3 Se 2 @NiCoPO electrode yields a specific capacity of 887.4 C g−1 at 1 A g−1, splendid rate capability of 86.2% capacity retention at 20 A g−1, along with a wonderful cycling stability of 91.1% over 5000 cycles. Besides, a Co 0.7 Fe 0.3 Se 2 @NiCoPO//porous carbon hybrid supercapacitor achieves a maximum energy density of 68.0 Wh kg−1 at 826.6 W kg−1 and outstanding long-term cycling performance with 95.7% initial capacity over 10,000 cycles. Our results propose an efficient approach to construct selenide/phosphate heterojunction with special morphology and nanostructure for advanced energy storage devices. [Display omitted] • 2D/2D heterojunction of Co 0.7 Fe 0.3 Se 2 @NiCoPO are synthesized. • Hierarchical Co 0.7 Fe 0.3 Se 2 @NiCoPO nanosheet arrays expose efficient surface area. • Synergy of dual components results in boosted capacitive properties. • Hybrid supercapacitor realizes an energy density of 68.0 Wh kg−1. [ABSTRACT FROM AUTHOR]

• FeCoSe 2 @NiCo-LDH core-shell nanosheet arrays are fabricated. • The heterostructure offers increased interfaces and rapid mass transfer. • Capacities of 220.9 and 184.4 mA h g−1 are yielded at 1 and 20 g−1. • Hybrid supercapacitor illustrates an energy density of 65.9 Wh kg−1. [Display omitted] For constructing high-performance hybrid supercapacitor devices, it is vital to exploit a battery-type cathode with enhanced kinetics and improved cyclic performance to match with a capacitive anode. Herein, highly porous FeCoSe 2 @NiCo-LDH core-shell nanosheet arrays were in situ decorated on face of carbon cloth via an electrodeposition approach and a selenylation treatment. The hierarchical heterostructure consisting of two types of vertically aligned interconnected two-dimensional nanosheets not only offers huge surface area and available diffusion pathways for quick electron/ion transport, but also generates plentiful heterointerfaces with modified electronic structure and enables synergetic effect between dual components. Consequently, the well-designed FeCoSe 2 @NiCo-LDH electrode displays a greatly boosted specific capacity of 220.9 mA h g−1 at 1 A g−1, 83.5% capacity retention at 20 A g−1, and wonderful cyclic stability, which are superior to those of single component. Furthermore, the hybrid supercapacitor device with a FeCoSe 2 @NiCo-LDH electrode and a hierarchical porous carbon electrode illustrates an extensive energy density of 65.9 Wh kg−1 at 1.248 kW kg−1 combined with long lifetime with 87.6% capacity retention over 10,000 cycles. These superb properties manifest that the integrated FeCoSe 2 @NiCo-LDH electrode owns a desirable application prospect in hybrid energy storage systems. [ABSTRACT FROM AUTHOR]

• Copper chloride was an efficient activator to prepare N, O, S self-doped porous carbons. • CuCl 2 activated hierarchical porous carbon exhibited large surface area of 1722.5 m2 g−1 and high yield of 39.6%. • A large specific capacitance and superior rate performance were achieved. • The symmetric supercapacitor showed high energy density of 30.4 Wh kg−1 under 496.0 W kg−1. ga1 Facile preparation of carbon-based electrode materials with high specific surface area and controllable pore structure through a green and mild strategy is highly desirable for high-performance supercapacitors. Here, hierarchically porous carbon materials were prepared by three types of metal chlorides, including ZnCl 2 , FeCl 3 , and CuCl 2. Compared with porous carbons obtained by traditional ZnCl 2 or FeCl 3 activation, hierarchically porous carbon obtained by a facile CuCl 2 activation possessed higher yield, larger specific surface area, more developed hierarchical pore structure, and higher heteroatom contents. Benefiting from the synergy of unique morphology, hierarchical pore architecture with abundant micro-/mesopores and coexistence of numerous redox-active nitrogen and sulfur funtionalities, the as-prepared hierarchically porous carbon activated by CuCl 2 exhibited superior electrochemical performance in aqueous electrolyte, including a large specific capacitance of 389.3 F g−1 at a current density of 1 A g−1, excellent rate capability and good cycling stability in a three-electrode system. Moreover, the assembled carbon-based symmetric supercapacitor based on CuCl 2 -activated carbon electrode delivered a significantly increased energy density of 30.4 Wh kg−1 at a power density of 496.0 W kg−1 in comparison to ZnCl 2 or FeCl 3 -activated carbon electrodes. Therefore, CuCl 2 activation is proved to be an effective chemical activation agent for the synthesis of biomass-derived carbon materials for high-performance supercapacitors. [ABSTRACT FROM AUTHOR]

The development of novel pseudocapacitve materials with optimal nanostructures has tremendous potential in enhancing the electrochemical properties of supercapacitors. Herein, NiHPO 3 ·H 2 O nanorods were prepared via an one-step hydrothermal method. Benefiting from its high electrical conductivity, unique one-dimensional rode-like morphology and hierarichical pore structure, NiHPO 3 ·H 2 O nanorods favor electron and ion transport and provide abundant electrochemical active sites for redox reactions. When applied as positive electrode for pseudocapacitor, the proposed NiHPO 3 ·H 2 O electrode shows a high specific capacitance of 1405.6 F g−1 at 1 A g−1, outstanding rate capability (64.2% capacitance retention at 10 A g−1) along with good cycling stability (77.3% capacitance retention after 5000 cycles). Furthermore, the assembled asymmetric supercapacitor using NiHPO 3 ·H 2 O as a positive electrode and pine pollen-derived hierarchical porous carbon as a negative electrode delivers a high energy density (42.6 Wh kg−1 at a power density of 449.1 W kg−1) and a long cycle life (84.7% retention after 10,000 cycles). These findings provide new opportunities to synthesize novel transition metal phosphites for supercapacitors. Image 1 • NiHPO 3 ·H 2 O nanorods were synthesized via hydrothermal reaction. • The unique nanostructure provides electrochemical active sites for redox reactions. • The NiHPO 3 ·H 2 O electrode delivers a specific capacitance of 1405.6 F g−1. • The constructed asymmetric supercapacitor exhibits an energy density of 42.6 Wh kg−1. [ABSTRACT FROM AUTHOR]

A facile activation method has been illustrated for the synthesis of porous carbons derived from orange peels using basic copper carbonate as activation agent. The resulting carbon material possesses a high specific surface area of 912.4 m2 g−1, hierarchical pore architecture with interconnected meso-/macropores, and a rich amount of nitrogen, oxygen and sulfur heteroatoms. Benefiting from to its unique pore structure and the co-existence of redox-active nitrogen, oxygen and sulfur functionalities, the obtained porous carbon shows outstanding electrochemical performance when used as electrode material for supercapacitors. The as-prepared porous carbon exhibits a high specific capacitance of 375.7 F g−1 at 1 A g−1 and good rate retention of 50.9% from 1 to 100 A g−1. Additionally, the assembled carbon-based symmetric supercapacitor delivers a high energy density of 31.3 W h kg−1 at a power density of 499.5 W kg−1 in 1.0 M Na 2 SO 4 electrolyte as well as superior long-term cyclic stability (only 7.3% of capacitance loss after 50,000 cycles within a voltage window of 0–2.0 V). This work provides an easy and feasible way for the synthesis of hierarchical porous carbon materials with both high power and energy density. Image 1 • Porous carbons were prepared via basic copper carbonate activation. • The obtained hierarchical porous carbon is large in specific surface area and high in N, O, S contents. • Both electric double layer capacitance and pseudocapacitance contribute to the high specific capacitance. • The assembled symmetric supercapacitor displays high energy density and excellent cycling stability. [ABSTRACT FROM AUTHOR]