Search

[Display omitted] • Amorphous/crystalline H-NiMoS 4 /NiS 2 hollow sphere was successfully constructed. • A high specific capacitance and good cycling performance was obtained. • The capacity retention of HSC was 83.7% after 20,000 cycles. • The HSC displayed a high energy density of 38.6 Wh kg−1 at 958.6 W kg−1. Phase engineering offers a promising strategy to tailor the physiochemical properties to further improve their electrochemical performance toward energy storage. However, it remains a challenge to fabricate well-defined amorphous/crystalline hetero-phase metal sulfides with high-density heterointerfaces. Herein, the synthesis of hetero-phase combination of amorphous NiMoS 4 and crystalline NiS 2 that possesses hollow nanosphere structure decorated by nanosheets (named as H-NiMoS 4 /NiS 2) is reported. Benefiting from the construction of the hollow nanosphere coated by nanosheets, amorphous/crystalline hetero-phase junction, and strong Ni-S hybridization, H-NiMoS 4 /NiS 2 electrode exhibits high specific capacity, outstanding rate capability and excellent cycling stability. Moreover, an all-solid-state supercapacitor was assembled with H-NiMoS 4 /NiS 2 as cathode and needle coke oxide (NCO) as anode, which can achieve remarkably high energy density of 38.6 Wh kg−1 at a power density of 958.6 W kg−1 and outstanding capacity retention of 83.7% after 20,000 cycling. The preparation of novel H-NiMoS 4 /NiS 2 nanomaterial with a hetero-phase of amorphous and crystalline provides a new solution for improving the structural stability and capacitor storage performance as electrodes for supercapacitors. [ABSTRACT FROM AUTHOR]

• NiCo 2 O 4 nanoparticles with different morphologies were prepared via template method and self-assembly method. • The NiCo 2 O 4 nanoparticles were in-situ decorated onto porous carbon (PC) and used as host of sulfur cathode for lithium sulfur battery. • The synergistic effect of physical binding of PC and adsorption catalysis of NiCo 2 O 4 nanoparticles could effectively improve the performance of lithium sulfur battery. Lithium-sulfur battery (LSB) is one of the most appealing candidates for advanced next-generation electrochemical energy storage systems based on the merits of extraordinary theoretical specific energy density, abundant resources and environmental friendliness of sulfur. However, the "shuttle effect" of lithium polysulfides (LiPSs) and low utilization of sulfur cathode severely plague the large-scale commercialization of the LSBs. In this work, a novel host material for sulfur cathode, namely porous carbon (PC) decorated with NiCo 2 O 4 nanoparticles (NiCo 2 O 4 /PC), was designed and prepared. Among all tested NiCo 2 O 4 nanoparticles with different morphologies, the NiCo 2 O 4 nanoparticles with honeycomb pore shape (C-NiCo 2 O 4) showed excellent performance as sulfur cathode host. Benefiting from the synergistic advantages between PC and C-NiCo 2 O 4 nanoparticles, the C-NiCo 2 O 4 /PC host materials showed strong adsorption for LiPSs, promising the alleviation of shuttle effect and promoting the catalytic conversion process of LiPSs. As a result, the LSBs with S@C-NiCo 2 O 4 /PC cathode delivered a high specific capacity of 1065.2 mAh g−1 at 0.1C, a stable cycling over 500 cycles with low fading rate of 0.053% per cycle at 0.5C and an enhanced rate capability compared with those of S@C-NiCo 2 O 4 and S@PC cathodes. This work demonstrated the synergistic effect of physical shackle from PC and adsorption-catalysis from NiCo 2 O 4 nanoparticles, which might provide new insights into the optimization of carbonaceous architecture for rationally regulating the polysulfide redox reactions. [ABSTRACT FROM AUTHOR]

• The hierarchical M-ZCOH/NPG/NF heterostructures were successfully constructed. • The BIEF in the heterointerface enhanced electronic/ionic transport dynamics. • A high capacity reaching ∼1247.1C g−1 (∼2771.3 F g−1) at 1 A g−1 was obtained. • The HSC displayed ultrahigh energy density of ∼78.3 Wh kg−1 at ∼800 W kg−1. The superior electronic/ionic transport dynamics of electrode materials have been crucial to achieve appealing high performance for supercapacitors. Herein, a fascinating one-dimensional (1D) zinc cobalt hydroxide nanobelts/0D irregular manganese dioxide nanoparticles (M-ZCOH) have been vertically loaded into the 3D Ni foam (NF) substrate wrapped by nitrogen-doped graphene (NPG) (M-ZCOH/NPG/NF) for supercapacitors. The ingeniously designed M-ZCOH/NPG/NF composites feature powerful built-in electric field (BIEF) introduced by well-defined heterointerface with abundant oxygen vacancies defects. The formed electron accumulation triggering strong interfacial interaction verified by the differential charge density analysis may endow M-ZCOH/NPG/NF with the extra driving force to increase the diffusion/adsorption of electrolyte ions, thereby facilitating electron/ion transfer kinetics. Also, the qualitative negative shift of the d band center for M-ZCOH composites further evidences a lower electron/ion transfer barrier compared with the monomers. Obviously, the penetrating understanding of heterointerface on the improved properties is manifestly interpreted by combining theoretical and experimental analysis. Moreover, the ingenious strategy of engineering the heterointerfaces in unique heterostructure with rich defects may provide a new prospect for optimizing other advanced materials in sustainable energy storage systems. [ABSTRACT FROM AUTHOR]

Lithiophilic COF@PP separator (TpPa-SO 3 H@PP) was prepared through the strategy combining with in-situ interfacial polymerization reducing the interfacial resistance and lithiophilic groups engineering which can suppress the shuttle effect and facilitate Li+ migration, and it exhibits superior performances. [Display omitted] • In situ interfacial synthesis promotes on preparing COF or POP modified PP separator. • Lithiophilic groups prominently facilitate Li+ transport and suppress shuttle effect. • Batteries with modified separators exhibit superior electrochemical performances. Lithium–sulfur batteries have been considered one of the most promising energy storage devices because of their high energy density (2600 W·h·kg−1), low cost, and the environmental friendliness of sulfur. However, the shuttle effect caused by the soluble polysulfide produced by the sulfur cathode in the redox process seriously affects the commercialization of the battery. To solve such problems, we designed and synthesized a lightweight covalent organic framework (COF)–based TpPa–SO 3 H@PP separator through in situ interfacial polymerization. Benefiting from the lithiophilic –SO 3 H groups, which are arranged in the nanochannels of the TpPa–SO 3 H COF, the TpPa–SO 3 H@PP separator not only suppresses the shuttle of polysulfide but also facilitates Li+ migration. Moreover, the good wettability of the electrolyte to the TpPa–SO 3 H@PP separator resulted in a lower interfacial resistance and higher ionic conductivity, ensuring a higher energy density. Based on the above advantages, cells with the TpPa–SO 3 H@PP separator showed an initial specific capacity of 863.97 mAh g−1 at 1C, and a capacity of 645.62 mAh g−1 after 500 cycles, and the average capacity decay rate of each cycle was only 0.05%, indicating superior cycling performance. Significantly, we extended the in situ interfacial polymerization to the preparation of a lithiophilic amorphous porous organic polymer (POP)–based TpPa–COOH@PP separator, which also has good performance, demonstrating the universality and effectiveness of in situ interfacial polymerization. This work opens a new route to prepare lithiophilic COF@PP and POP@PP separators with a lower shuttle effect and higher ion transport via in situ interfacial polymerization for high–performance Li–S batteries. [ABSTRACT FROM AUTHOR]

[Display omitted] • Fly ash-based transition metal silicate is prepared by a synergistic strategy. • The crystalline SiO 2 of fly ash turns into Ca 2 SiO 4 with high-temperature roasting. • The uniformly dispersed carbon nanofibers cover surface by electrostatic assembly. • The heterostructure and S doping enhance the internal conductivity of material. • The composite shows a high specific capacitance of 493.33 F·g−1 at 0.5 A·g−1. Based on the high-calcium fly ash of an actual coal-fired power plant, the crystalline silica is successfully transformed into cobalt-iron silicate, and then CNFs/FA-CoFeSiSx with good energy storage performance is obtained by modifying the cobalt-iron silicate as the electrode material of supercapacitor. The crystalline silica is successfully converted to silicate (Ca 2 SiO 4) by high-temperature calcination with NaHCO 3 and fly ash. Meanwhile, a 3D porous structure of fly ash is obtained by etching. Ion exchange is successfully carried out by the one-step hydrothermal method, which realizes the transition of Ca 2 SiO 4 to Co 2 SiO 4 and Fe 2 SiO 4. The further modification through electrostatic self-assembly and sulfurization process significantly increases the electron migration rates. The situation that fly ash is difficult to be used in energy storage is ameliorated by the coordinated regulation of various strategies. The final product CNFs/FA-CoFeSiSx exhibited a high specific capacitance (493.33 F·g−1 at 0.5 A·g−1), high Coulombic efficiency (about 100% at 10 A·g−1), and good cycle performance (79.50% capacitance retention after 1800 cycles). Finally, a solid-state asymmetric supercapacitor is assembled based on CNFs/FA-CoFeSiSx as the positive electrode and commercial active carbon as the negative electrode, which performs the maximum energy density of 25.43 Wh·kg−1 and power density of 359.07 W·kg−1. Considering the good energy storage characteristics of fly ash electrode materials, this work provides a low-cost preparation method for electrochemical energy storage and realizes the high-value utilization of fly ash. [ABSTRACT FROM AUTHOR]

[Display omitted] • A nitrilotriacetic acid-assisted strategy for controllable synthesis of NiS/carbon hexahedrons was proposed. • Synchronous realization of the combination of carbon with NiS and morphology controlled in one step. • Formation mechanism and determinants of NiS/carbon composites are revealed. • Enhanced power density (4187.2 W kg−1) and energy density (30.8 Wh kg−1). Effective adjustment of structure and morphology is considered to be an available strategy to improve the energy storage performance of supercapacitor electrode materials. Herein, a series of hierarchical NiS/carbon hexahedrons consist of self-assembling nanoplates or nanorods were synthesized via nitrilotriacetic acid (NTA)-assisted hydrothermal strategy. This study demonstrates that the micro-morphology of the unit structure constituting the hexahedrons can be controlled by adjusting the concentration of NTA. Benefiting from synergetic effect of high void space, hierarchical assembly mode and integrated composite structure, NiS/carbon hexahedrons promote adequate exposure of abundant active sites and enhance the structural stability, donating superior energy storage performance. As expected, the optimized NiS/carbon electrode (NiS/NTA-2) exhibits superb capacitive performance, including excellent specific capacitance of 1530.4 F g−1 at 1.0 A g−1 and remarkable cycle stability with 85.6% after 5000 cycles. Employing the as-prepared NiS/NTA-2 composites as positive electrode, the hybrid supercapacitor device with spectacular capacity of maximum energy density and power density up to 35.1 Wh kg−1 and 4509.3 W kg−1 and impressive long-term stability of 87.2% retention after 5000 cycles is assembled. Moreover, a light-emitting diode (LED) is successfully illuminated for up to 12 min by two devices connected in series. Based on this strategy, high-performance energy storage devices can be further developed through utilizing the modulation effect of metal complexes to design morphology controlled electrode materials. [ABSTRACT FROM AUTHOR]

• The doping of SSN increased the band gap width and decreased the grain size. • The ceramic possesses an energy density of 4.42 J/cm3 and an efficiency of 60%. • The transmittance of the ceramic is 76.7% and 84.5% at 780 and 1378 nm, respectively. • 0.825KNN-0.175SSN ceramic exhibited a small strain effect of 0.022%. Lead-free transparent ferroelectric ceramics with superior energy storage properties are highly desirable for pulsed power technologies and the increased optical transparency demand. However, the transparency and energy storage density of lead-free bulk ceramics cannot meet the requirements of their wide applications due to the coarse microstructure and relatively low breakdown strength. In this study, a design strategy is proposed to optimize the energy storage characteristics and transparency of ceramics by introducing nanodomains, increasing the band gap energy and reducing the grain size. The results showed that submicron grain (0.21 μm) and large band gap energy (E g = 3.21 eV) were achieved through the introduction of the second component Sr(Sc 0.5 Nb 0.5)O 3 (SSN). An excellent transparency of up to 84.5% in the near-infrared region (1378 nm), a high energy density (W) of ~4.42 J·cm−3 and an extremely small strain of ~0.022% were simultaneously achieved in the 0.825(K 0.5 Na 0.5)NbO 3 -0.175Sr(Sc 0.5 Nb 0.5)O 3 (0.825KNN-0.175SSN) ceramics. These results revealed the potential applications of (K 0.5 Na 0.5)NbO 3 -based ceramics for energy storage and provide a feasible approach of domain engineering to develop new lead-free energy storage transparency materials. [ABSTRACT FROM AUTHOR]