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• Fiber-shaped dye-sensitized solar cell (FDSC) comprises PVdF-HFP gel electrolyte. • Gel electrolyte configuration is controlled by using different PVdF-HFP amounts. • Gel electrolyte is defined as the porous layer and the concrete layer of polymer. • I 2 amount is optimized considering redox ability and electrolyte transmittance. • A conversion efficiency of 6.32% is got for FDSC with 9% PVdF-HFP and 0.04 M I 2. Efficient energy generation device is desired to couple with soft electronics for driving devices. Due to frequent uses of soft electronics in indoor conditions, flexible fiber-shaped dye-sensitized solar cell (FDSC) is regarded as the most promising energy generation device due to high light-to-electricity conversion maintenance under weak dim light. Using gel electrolyte to assemble FDSC cannot only restrict electrolyte leakage but also improve device flexibility and stability especially under bending conditions. In this study, poly(vinylidene fluoride- co -hexafluoropropylene) (PVdF-HFP) gel electrolyte is used to fabricate FDSC composed of curled TiO 2 nanotube/Ti wire photoanode and Pt counter electrode. It is the first time to control gel electrolyte configuration by adding different PVdF-HFP concentrations, and to optimize iodine concentration in electrolyte regarding to redox ability and electrolyte transmittance. Configuration of gel electrolyte is carefully analyzed to define porous layer and concrete layer of polymer for accumulating liquid electrolyte and inhibiting leakage and evaporation. The highest solar-to-electricity conversion efficiency of 6.32% is obtained for FDSC with 9% PVdF-HFP and 0.04 M I 2 in electrolyte, due to well-defined cross-linking structure, abundant redox reactions, and high incident-light illumination through electrolyte. Electrochemical impedance spectroscopy and intensity-modulated photocurrent/photovoltage spectroscopy are used to analyze charge-transfer resistance and charge-collection efficiency. [ABSTRACT FROM AUTHOR]

Graphical abstract Abstract The Ni foam can act as the nickel ion source and the current collector for synthesizing Ni-based compounds using the hydrothermal synthesis especially in the acid condition. Using Ni foam as the Ni2+ source can grow materials on the substrate directly and uniformly since nickel ions are released from substrate thoroughly. Nickel-based bimetallic oxides are intensively investigated as battery-type materials for battery supercapacitor hybrid devices (BSHD) because of high electrical conductivities and abundant transition states for inducing multiple redox reactions. In this study, Mo, Mn, Al, and W precursors are simply added in Ni precursor-free acid solution for hydrothermal synthesis using Ni foam as the nickel ion source and the current collector to synthesize Ni-based bimetallic oxide electrodes for BSHD. The morphology of nickel-based bimetallic oxide prepared with and without incorporating the structure-directing agent is also carefully discussed. The highest specific capacitance (C F) of 1.80 F/cm2 corresponding to the capacity of 4.54 mAh/cm2 at 5 mA/cm2 is attained for the nickel molybdenum oxide (Ni-Mo oxide) electrode. The Ni-Mo oxide-based BSHD shows a potential window of 1.8 V, a C F value of 223.53 mF/cm2 corresponding to the capacity of 1.45 mAh/cm2 at 5 mA/cm2, the maximum energy density of 4.60 Wh/kg at the power density of 0.21 kW/kg, and the C F retention of 90% after 6000 times charging/discharging process. [ABSTRACT FROM AUTHOR]

Graphical abstract Impressive synergic effect was got by incorporating HQ and PPD redox additives in H 2 SO 4 as electrolyte for supercapacitors with activated carbon electrodes prepared using LA132. Abstract Activated carbon (AC) with large surface area and high electrical conductivity is widely applied on supercapacitors (SC), but the energy storage mechanism for the pure electrical double layer capacitor of carbon leads to a low energy density. Developing stable aqueous electrolytes with abundant redox reactions via incorporating more than one redox additive in the electrolyte is one of the efficient strategies to improve the energy storage capacity of the AC-based SC. In this study, the dual redox additives of hydroquinone (HQ) and p-phenylenediamine (PPD) are incorporated in the aqueous solution as the electrolyte for SC. The effects of the aqueous solution type as well as the total redox additive concentration and the relative amounts of HQ and PPD on the electrochemical performance of SC are carefully studied. Two binders are used for assembling the AC electrodes, and the binder-dependent electrochemical behaviors and energy storage capabilities for SC are obtained. The symmetric SC assembled with the optimized electrolyte and the AC electrode prepared using the LA132 binder shows the potential window of 1.6 V, the specific capacitance of 116.23 F/g at 2 A/g, and the maximum energy density of 1.85 W h/kg at the power density of 0.15 kW/kg. [ABSTRACT FROM AUTHOR]

The nickel cobalt sulfide is one of the most attractive electroactive materials for battery-like electrodes with multiple oxidation states for Faradaic reactions. Novel structures of the nickel cobalt sulfide with large surface areas and high conductivities have been proposed to improve the performance of the battery-like electrodes. The hydrothermal reaction is the most common used method for synthesizing nickel cobalt sulfide nanostructures due to the simple and cost-effective features, but the precursor concentration on the morphology and the resulting electrochemical performance is barely discussed. In this study, various Ni to Co ratios are used in the hydrothermal reaction to make nickel cobalt sulfides on the nickel foam, and the Ni to Co ratio is found to play great roles on the morphology and the electrocapacitive performance for the pertinent battery-like electrodes. The sheet-like structures are successfully obtained with large surface area for charge accumulation, and the optimized sample presents the largest nanosheets among all with several wrinkles on the surface. A high specific capacity of 258.2 mAh/g measured at the current density of 5 A/g and a high-rate charge/discharge capacity are also attended for the optimized battery-like electrodes. The excellent cycling stability of 94.5% retention after 2000 cycles repeated charge/discharge process is also obtained for this system. [ABSTRACT FROM AUTHOR]

Nickel cobalt fluoride decorating ammonia ions (NCNF) with excellent energy storage ability is proposed by incorporating ammonia fluoride during synthesizing ZIF-67 in our previous work. It is necessary to modify NCNF for achieving better energy storage ability and widen its application. In this study, sulfurization and copper decoration are firstly adopted to enhance energy storage ability of NCNF. Without Cu decoration, aggregations completely convert to separated nanoparticles at sulfurization temperature of 160°C, which also shows partial conversion of NCNF to cobalt sulfide. The highest specific capacitance (C F) of 1666.1 ​F/g (277.7 mAh/g) is achieved for optimized NCNF-derived sulfide, and untreated NCNF electrode only shows a C F value of 519.8 ​F/g (277.7 mAh/g), due to partial sulfurization of the former case with high electrocapacitive property of NCNF and high electrical conductivity of sulfide. Copper is then incorporated using one-step and two-step hydrothermal processes. However, the best performed copper-decorated NCNF-derived sulfide electrode only shows a C F value of 508.5 ​F/g (84.8 mAh/g), due to the dominated formation of copper sulfide and limited appearances of cobalt sulfide and NCNF. A symmetric energy storage device comprising optimized NCNF-derived sulfide electrodes presents a maximum energy density of 8.64 ​Wh/kg at 2.16 ​kW/kg and high capacitance retention of 125% after 13,000 cycles. [Display omitted] • Novel Ni–Co fluoride with NH 4 + (NCNF) is proposed by adding NH 4 F for making ZIF67. • Sulfurization and copper decoration are used to enhance energy storage of NCNF. • Highest specific capacitance of 1666.1 ​F/g (277.7 mAh/g) is got for NCNF-sulfide. • The best performed Cu–NCNF-sulfide only shows C F value of 508.5 ​F/g (84.8 mAh/g). • Symmetric device with NCNF-sulfide shows the C F retention of 125% in 13000 cycle. [ABSTRACT FROM AUTHOR]

[Display omitted] Transition metal borides (TMBs) with high theoretical capacitances and excellent electronic properties have attracted much attention as a promising active material of supercapacitors (SCs). However, TMB nanoparticles are prone to conduct self-aggregation, which significantly deteriorates the electrochemical performance and structural stability. To address the severe self-aggregation in TMBs and improve the active material utilization, it is imperative to provide a conductive substrate that promotes the dispersion of TMB during growths. In this work, sheet-like nickel cobalt boride (NCB) was grown on molybdenum disulfide (MoS 2) hollow spheres (H-MoS 2) by using simple template growth and chemical reduction methods. The resultant NCB/H-MoS 2 -50 was observed with uniform NCB nanosheets structure on the surface of the H-MoS 2 and stronger M B bonding. After optimizing the loading amount of H-MoS 2 , the optimal composite (NCB/H-MoS 2 -50) modified nickel foam (NF) exhibits a superior specific capacity (1302 C/g) than that of the NCB electrode (957 C/g) at 1 A/g. Excellent rate capability of 84.8% (1104 C/g at 40 A/g) is also achieved by the NCB/H-MoS 2 -50 electrode. The extraordinary electrochemical performance of NCB/H-MoS 2 -50 is credited to the unique nanosheet-covered hollow spheres structure for facilitating ion diffusion and versatile charge storage mechanisms from the pseudocapacitive behavior of H-MoS 2 and the Faradaic redox behavior of NCB. Furthermore, a hybrid SC is assembled with NCB/H-MoS 2 -50 and activated carbon (AC) electrodes (NCB/H-MoS 2 -50//AC), which operates in a potential window up to 1.7 V and delivers a high energy density of 76.8 W h kg−1 at a power density of 850 W kg−1. A distinguished cycling stability of 93.2% over 20,000 cycles is also obtained for NCB/H-MoS 2 -50//AC. These findings disclose the significant potential of NCB/H-MoS 2 -50 as a highly performed battery-type material of SCs. [ABSTRACT FROM AUTHOR]

Cobalt tetrafluoroborate was proposed as a novel bi-functional precursor for synthesizing ZIF-67 derivatives, and interactions between solvent molecules and solutes on morphology, composition, and electrochemical performance are investigated. [Display omitted] • Co(BF 4) 2 is proposed as a novel cobalt precursor to synthesize ZIF67 derivatives. • Co(BF 4) 2 can supply cobalt ions and structure directing agent function from BF 4 −. • Deionic water, methanol and ethanol are used as precursor solvent to study effect. • The optimal derivative presents a specific capacitance of 608.3 F/g at 20 mV/s. • A battery supercapacitor hybrid shows maximum energy density of 45 Wh/kg@429 W/kg. Metal-organic framework (MOF) derivatives with tunable pore structure and improved conductivity are intensively designed as electroactive materials. Incorporating structure directing agents (SDA) is beneficial for designing MOF derivatives with excellent electrochemical performances. Ammonium fluoroborate has been reported as an effective SDA, coupled with cobalt salt and 2-methylimidazole, to synthesize zeolitic imidazolate framework-67 (ZIF-67) derivatives for charge storage. However, the synthetic environment for growing cobalt-based active materials is relatively complex. In this study, cobalt tetrafluoroborate (Co(BF 4) 2) is proposed as a novel cobalt precursor, supplementing cobalt ions and acting as the SDA in a single chemical, to synthesize the cobalt-based electroactive material of energy storage electrodes. Interactions between solvent molecules and solutes play significant roles on the morphology, composition, and electrochemical performance of active materials. Deionized water, methanol and ethanol are used as precursor solvents to understand their effects on material and electrochemical properties. The optimal electrode presents a specific capacitance of 608.3 F/g at 20 mV/s, attributed to the highest electrochemical surface area and evident compositions of cobalt fluoride and hydroxide. A battery supercapacitor hybrid achieves the maximum energy density of 45 Wh/kg at 429 W/kg. The C F retention of 100% and Coulombic efficiency of 99% are achieved after 10,000 cycles. [ABSTRACT FROM AUTHOR]

Sn x P y particles are in-situ encapsulated into MXene conductive networks by hydrothermal and phosphorization processes as novel anode materials of the sodium ion battery. MXene amounts and hydrothermal durations were investigated to evenly distribute Sn x P y in MXene. [Display omitted] • Sn x P y particles are in-situ encapsulated into MXene conductive network (Sn x P y /MXene). • MXene ratio and hydrothermal duration is studied to evenly distribute Sn x P y in MXene. • Sn x P y /MXene has capacities of 438.8 and 314.1 mAh/g at 0.2 and 1.0 A/g, respectively. • Capacity retentions of 6.0 % and 73.6 % are respectively got for Sn x P y and Sn x P y /MXene. • Sn x P y has smaller volume expansion and MXene self-stacking is reduced in Sn x P y /MXene. Sodium-ion battery (SIB) is one of potential alternatives to lithium-ion battery, because of abundant resources and lower price of sodium. High electrical conductivity and long-term durability of MXene are advantageous as the anode material of SIB, but low energy density restricts applications. Tin phosphide possesses high theoretical capacity, low redox potential, and large energy density, but volume expansion reduces its cycling stability. In this study, tin phosphide particles are in-situ encapsulated into MXene conductive networks (Sn x P y /MXene) by hydrothermal and phosphorization processes as novel anode materials of SIB. MXene amounts and hydrothermal durations are investigated to evenly distribute Sn x P y in MXene. After 100 cycles, Sn x P y /MXene reaches high specific capacities of 438.8 and 314.1 mAh/g at 0.2 and 1.0 A/g, respectively. The capacity retentions of 6.0% and 73.6% at 0.2 A/g are respectively obtained by Sn x P y and Sn x P y /MXene. The better specific capacity and cycling stability of Sn x P y /MXene are attributed to less volume expansion of Sn x P y during charge/discharge processes and relieved self-stacking of MXene by encapsulating Sn x P y particles between MXene layers. Electrochemical impedance spectroscopy and Galvanostatic intermittent titration technique are also applied to analyze the charge storage mechanism in SIB. Higher sodium ion diffusion coefficient and smaller charge-transfer resistance are obtained by Sn x P y /MXene. [ABSTRACT FROM AUTHOR]

Two novel structure directing agents (NH 4 BF 4 and NH 4 HF 2) and six metal species of Al, Mn, Co, Ni, Cu and Zn are coupled to synthesize metal organic framework derivatives for energy storage. The Ni-HBF shows the highest specific capacitance of 698.0F/g at 20 mV/s. [Display omitted] • Metal organic framework derivatives are made by 2-methylimidazole, NH 4 BF 4 and NH 4 HF 2. • Metals of Al, Mn, Co, Ni, Cu and Zn are used to make materials for energy storage. • Ni-based derivative shows a highest specific capacitance (C F) of 698.0F/g (20 mV/s). • Device with Ni-based electrode has maximum energy density of 27.9 Wh/kg at 325 W/kg. • A C F retention of 170.9% and Coulombic efficiency of 93.2% are got in 10,000 cycles. Tailoring morphology and composition of metal organic frameworks (MOF) can improve energy storage by establishing high surface area, large porosity and multiple redox states. Structure directing agents (SDA) is functional of designing surface properties of electroactive materials. Ammonium fluoride has functional abilities for designing MOF derivatives with excellent energy storage abilities. Systematic design of MOF derivatives using ammonia fluoride-based complex as SDA can essentially create efficient electroactive materials. Metal species can also play significant roles on redox reactions, which are the main energy storage mechanism for battery-type electrodes. In this work, 2-methylimidazole, two novel SDAs of NH 4 BF 4 and NH 4 HF 2 , and six metal species of Al, Mn, Co, Ni, Cu and Zn are coupled to synthesize MOF derivatives for energy storage. Metal species-dependent compositions including hydroxides, oxides, and hydroxide nitrates are observed. The nickel-based derivative (Ni-HBF) shows the highest specific capacitance (C F) of 698.0F/g at 20 mV/s, due to multiple redox states and advanced flower-like surface properties. The diffusion and capacitive-control contributions of MOF derivatives are also analyzed. The battery supercapacitor hybrid with Ni-HBF electrode shows a maximum energy density of 27.9 Wh/kg at 325 W/kg. The C F retention of 170.9% and Coulombic efficiency of 93.2% are achieved after 10,000 cycles. [ABSTRACT FROM AUTHOR]

[Display omitted] • S-doped Ni Co layered double hydroxide and PPy nanotubes (NiCo-LDH-S/PNTs) was made. • Zeolitic imidazolate framework-67 give Co and template of sheet-assembled polyhedron. • NiCo-LDH-S/PNTs shows the highest specific capacitance (C F) of 1936.3F/g at 10 mV/s. • Battery supercapacitor hybrid shows maximum energy density of 16.3 Wh/kg at 650 W/kg. • The C F retention of 74% and Coulombic efficiency of 90% are got after 8,000 cycles. Nickel and cobalt layered double hydroxide (NiCo-LDH) has large specific surface area and interlayer spacing, multiple redox states and high ion-exchange capability, but poor electrical conductivity, severe agglomerations and structural defect restrict energy storage ability of NiCo-LDH as active materiel of battery supercapacitor hybrids (BSH). In this study, it is the first time to design sulfur-doped NiCo-LDH and polypyrrole nanotubes composites (NiCo-LDH-S/PNTs) from zeolitic imidazolate framework-67 (ZIF-67) as the efficient active material of BSH using electrospinning and hydrothermal processes. Effects of sulfur doping amounts are investigated. The one-dimensional hollow polypyrrole decorated with NiCo-LDH-S sheets with high aspect ratio provides straight charge-transfer routes and abundant contacts with electrolyte. The highest specific capacitance (C F) of 1936.3 F/g (specific capacity of 322.8 mAh/g) is achieved for the NiCo-LDH-S/PNTs with sulfur doping amount of 7% at 10 mV/s. The BSH comprising graphene LDH negative electrode and NiCo-LDH-S/PNTs positive electrode shows the maximum energy density of 16.28 Wh/kg at 650 W/kg. The C F retention of 74% and Coulombic efficiency of 90% are also achieved after 8000 charge/discharge cycles. [ABSTRACT FROM AUTHOR]

[Display omitted] • W-doped BiVO 4 coupling MIL-101 (Fe) is made as photocatalyst for water oxidation. • Optimizing W amounts can increase carriers without creating recombination sites. • MIL-101 reduces recombination, create active sites and improve oxidation kinetics. • A high photocurrent density of 4.00 mA/cm2 at 1.23 V RHE under AM 1.5G was obtained. • Photocurrent retention higher than 95.5% is obtained under illumination for 6300 s. Doping heteroatoms and decorating co-catalyst are intensively applied to improve photocatalytic ability of BiVO 4. In this study, it is the first time to design W-doped BiVO 4 coupling MIL-101(Fe) as photocatalyst for water oxidation using electrodeposition and hydrothermal processes. Similar system with Mo as dopant has been reported, but the dopant plays important roles on electrochemical performance. It is worthy to study the efficient system with different dopant. Doping amount of W is optimized to achieve high carrier density without creating serious recombination sites. MIL-101(Fe) is decorated on W-doped BiVO 4 to suppress surface recombination, create accessible active sites and improve water oxidation kinetics. Optimized W-doped BiVO 4 /MIL-101(Fe) electrode shows a high photocurrent density of 4.00 mA/cm2 at 1.23 V versus reversible hydrogen electrode (V RHE) under air mass 1.5-global simulated light illumination without hole scavenger in electrolyte, due to large electrochemical surface area, high carrier density and small charge-transfer resistance. The W-doped BiVO 4 and BiVO 4 electrodes merely show photocurrent densities of 2.96 and 1.72 mA/cm2 at 1.23 V RHE , respectively. Photocurrent retention higher than 95.5% is obtained for W-doped BiVO 4 /MIL-101 (Fe) electrode under continuous illumination for 6300 s, suggesting lasting photocatalytic ability of this novel W-doped BiVO 4 /MIL-101(Fe) electrode. [ABSTRACT FROM AUTHOR]

[Display omitted] High surface area and tunable pore size are beneficial for metal organic frameworks (MOFs) as electroactive material of energy storage devices. Novel ZIF67 derivative proposed in our previous work, nickel cobalt fluoride coupled with ammonia ions (NCNF), is synthesized using ammonia fluoride to solve poor electrical conductivity of MOFs. MXene is commonly incorporated in pseudo-capacitive materials to enhance electrical conductivity and energy storage ability. In this study, it is the first time to design MXene and NCNF composites (MXene/NCNF) with different MXene amounts via incorporating MXene in growing process of NCNF. MXene and NCNF are combined via self-assembly in a simple room temperature solution process. The optimized MXene/NCNF electrode shows a higher specific capacitance of 1020.0 F g−1 (170.0 mAh g−1) than that of NCNF electrode (574.2 F g−1 and 95.7 mAh g−1) at 20 mV s−1, due to excellent surface properties of MXene/NCNF with conductive network of MXene and high electrocapacitive performance of NCNF. A symmetric energy storage device composed of the optimized MXene/NCNF electrodes presents outstanding cycling stability with Coulombic efficiency of 100% during whole cycling process and a high capacitance retention of 99% after 6000 cycles. Excellent electrochemical performance and simple synthesis of MXene/NCNF open new blueprints for designing novel electrocapacitive materials for electrochemical applications. [ABSTRACT FROM AUTHOR]

Zeolitic imidazolate framework-67 (ZIF67) with large surface area and tunable pore structure is intensively applied as a tailoring target for design active materials. An in-situ tailoring technique is proposed to design ZIF67 derivatives by using structure directing agents (SDA) to induce favorable morphology and composition. Ammonium fluoride is a common SDA for modifying surface properties of active materials. With the same ammonium and similar fluorine-based groups, NH 4 BF 4 and NH 4 HF 2 are priming to play as SDA for synthesizing ZIF67 derivatives. In this study, the synthetic process of ZIF67 derivatives is tailored by varying the precursor concentration and reaction time in systems with NH 4 BF 4 and NH 4 HF 2 as SDA. The precursor concentration plays significant roles in the composition of ZIF67 derivatives. The reaction duration has higher influences on the morphology. The highest specific capacitance (C F) of 1347.0 F/g at 20 mV/s is achieved for the ZIF67 derivative synthesized using low concentration and 18 h, owing to favorable cobalt and nickel hydroxide compositions and two-dimensional sheet-like structure. An energy storage device composed of the optimal ZIF67 derivative and carbon electrodes shows a maximum energy density of 11.96 Wh/kg at 650 W/kg. The excellent cycling stability with C F retention of 83.6% and Coulombic efficiency of 92.0% is obtained after 10000 cycles. A series ZIF67 derivatives were synthesized using different precursor concentrations and reaction durations in the environment containing NH 4 BF 4 , NH 4 HF 2 and 2-methylimidazole. Metal hydroxide and ZIF-L-Co compositions were respectively obtained by using low and high concentrations for synthesis. Reaction time has less impacts on the composition of ZIF67 derivatives but has large influences on morphology of ZIF67 derivatives. [Display omitted] • NH 4 BF 4 and NH 4 HF 2 are structure directing agents (SDA) for making ZIF67 derivatives. • ZIF67 derivatives are optimized regarding precursor concentration and reaction time. • Precursor concentration plays significant roles in composition of ZIF67 derivatives. • The highest specific capacitance (C F) of 1347.0 F/g is got for the ZIF67 derivative. • A C F retention of 83.6% and Coulombic efficiency of 92.0% is got after 10000 cycles. [ABSTRACT FROM AUTHOR]

[Display omitted] Zeolitic imidazolate framework-67 (ZIF67) derivatives are considered as promising active materials for energy storage owing to the possible formation of cobalt oxide and N -doped graphite. Cobalt oxide has multiple redox states for generating redox reactions for charge storage, while N -doped graphite can provide high electrical conductivity for charge transfer. In this study, it is the first time to synthesize binder-free electrodes composed of cobalt oxide and N -doped graphite derived from ZIF67 on carbon cloth (CC) for supercapacitor (SC). Successive oxidation and carbonization along with additional coverage of ZIF67 derivatives are applied to synthesize ZIF67 derivatives composed of cobalt oxide, N -doped graphite and cobalt oxide/ N -doped graphite composites with different layer compositions. The highest specific capacitance (C F) of 90.0F/g at 20 mV/s is obtained for the oxidized ZIF67/carbonized ZIF67/carbon cloth (O67/C67/CC) electrode, due to the large surface area and high electrical conductivity benefitted from preferable morphology and growing sequence of Co 3 O 4 and N -doped graphite. The symmetric SC composed of O67/C67/CC electrodes shows the maximum energy density of 2.53 Wh/kg at the power density of 50 W/kg. Cycling stability with C F retention of 70% and Coulombic efficiency of 65% after 6000 times repeatedly charge/discharge process is also obtained for this symmetric SC. [ABSTRACT FROM AUTHOR]

[Display omitted] Lithium iron phosphate (LFP) is one of the promising cathode materials of lithium ion battery (LIB), but poor electrical conductivity restricts its electrochemical performance. Carbon coating can improve electrical conductivity of LFP without changing its intrinsic property. Uniform coating of carbon on LFP is significant to avoid charge congregation and unpreferable redox reactions. It is the first time to apply the commercial organic binder, Super P® (SP), as carbon source to achieve uniform coating on LFP as cathode material of LIB. The simple and economical mechanofusion method is firstly applied to coat different amounts of SP on LFP. The LIB with the cathode material of optimized SP-coated LFP shows the highest capacity of 165.6 mAh/g at 0.1C and 59.8 mAh/g at 10C, indicating its high capacity and excellent high-rate charge/discharge capability. SP is applied on other commercial LFP materials, M121 and M23, for carbon coating. Enhanced high-rate charge/discharge capabilities are also achieved for LIB with SP-coated M121 and M23 as cathode materials. This new material and technique for carbon coating is verified to be applicable on different LFP materials. This novel carbon coating method is expected to apply on other cathode materials of LIB with outstanding electrochemical performances. [ABSTRACT FROM AUTHOR]

Copper sulfide with ease fabrication, low cost and high electrocapacitive behavior has been widely applied as electrocapacitive material of battery supercapacitor hybrids (BSH). Several morphologies are designed to achieve excellent surface properties and high energy storage ability. Large specific surface area and vigorous pore structure are easier to attain by constructing three-dimensional morphologies especially with hollow features. In this study, novel copper sulfide plate-assembled hollow cages are synthesized using solution and hydrothermal processes. The cage structure is formed for copper sulfide prepared using different hydrothermal temperatures, but pure copper sulfide composition is obtained only by using hydrothermal temperature higher than 130 °C. With the preferable morphology and composition, the copper sulfide electrode synthesized using 130 °C (Cu– O –S130) shows the highest specific capacitance (C F) of 292.1 F/g at 20 mV/s and excellent rate performance. The Cu– O –S130 positive electrode and a carbon negative electrode are used to assemble a BSH, which reaches a maximum energy density of 22.4 Wh/kg at 500 W/kg and C F retention of 80% and Coulombic efficiency larger than 95% after 7000 cycles. This work provides blueprints for designing efficient morphology of copper sulfide to achieve excellent energy storage ability. [Display omitted] • Novel CuS plate-assembled hollow cage is made via solution and hydrothermal process. • Hydrothermal temperature effects on physical and electrochemical property is studied. • Cu– O –S130 electrode shows highest specific capacitance (C F) of 292.1 F/g at 20 mV/s. • Battery supercapacitor hybrid shows maximum energy density of 22.4 Wh/kg at 500 W/kg. • C F retention of 80% and Coulombic efficiency higher than 95% in 7000 cycles are got. [ABSTRACT FROM AUTHOR]

Universitetet i Oslo-66 (UiO-66) with high surface area and tunable pore structure is considered as one of efficient active materials of supercapacitors (SC). Carbonization is largely used to enhance electrical conductivity and energy storage ability of active material, but the parameters for carbonizing UiO-66 as active material of SC is rarely studied. It is the first time to investigate carbonization temperature effects on physical properties of UiO-66 derived carbon and electrochemical performances of SC. Applying higher temperatures for carbonizing UiO-66 leads to more serious structure shrinking, more defects and more C–O than C O bonds in carbon materials, but the recrystallization at 900 ​°C causes larger particle formation. The carbonized UiO-66 prepared using 800 ​°C (C800) shows the highest specific capacitance of 169.7 ​F/g at 20 ​mV/s, due to small particle size and suitable ratios of C–O to C O and graphene to defect. The SC composed of C800 electrodes shows maximum energy density of 2.55 ​Wh/kg at power density of 200 ​W/kg and excellent charge/discharge cycling stability with capacitance retention of 86.5% and Coulombic efficiency of 100% after 12000 times repeatedly charge/discharge process. Excellent bending ability is also achieved for this SC with capacitance retention of 74.3% after bending 500 times at 180°. [Display omitted] • UIO66 is carbonized at various temperature for supercapacitor (SC) at the first time. • Carbonizing UIO-66 at higher temperatures leads to reduced size and more defects. • Recrystallization of UIO66 at 900 ​°C leads to large particle and C O bond formation. • Carbonized UIO66 at 800 ​°C (C800) shows the highest C F value of 169.7 ​F/g at 20 ​mV/s. • SC comprising C800 electrodes shows maximum energy density of 2.55 ​Wh/kg at 200 ​W/kg. [ABSTRACT FROM AUTHOR]

Bimetallic oxides with multiple redox states and high theoretical capacitances have attracted attention as efficient electroactive material of supercapacitors (SC). MnCo 2 O 4 is applied on SC due to high oxidation potential and multiple oxidation states. One-dimensional nanotube can provide efficient charge-transfer path, large surface area and voids for ions confinements. In this study, it is firstly to synthesize MnCo 2 O 4 nanotubes using electrospinning and hydrothermal techniques for SC. Hydrothermal duration determines redox extents of ZIF67 and Mn precursor, while Mn concentration dominates particle amounts on nanotubes. The optimized MnCo 2 O 4 electrode shows the highest specific capacitance (C F) of 101.9 ​F/g at 20 ​mV/s and the best high-rate performance, due to complete conversion of ZIF67 and KMnO 4 as well as well-constructed particle-assembled wall. The symmetric SC presents a maximum energy density of 3.40 ​Wh/kg at 350 ​W/kg, and excellent cycling stability with Coulombic efficiency of 91.2% and C F retention of 91.2% in 5500 cycles. [Display omitted] • MnCo 2 O 4 nanotube is made via electrospinning and hydrothermal techniques for SC. • Hydrothermal duration decides redox extent of ZIF67 and Mn precursor in nanotubes. • Mn concentration dominates particle amounts on the wall of MnCo 2 O 4 nanotubes. • Optimal MnCo 2 O 4 electrode shows C F of 101.9 ​F/g and good high-rate performance. • SC shows Coulombic efficiency of 91.2% and C F retention of 91.2% in 5500 cycles. [ABSTRACT FROM AUTHOR]