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Lithium ion hybrid capacitors (LIHCs) have a capacitor-type cathode and a battery-type anode and are a prospective energy storage device that delivers high energy/power density. However, the kinetic imbalance between the cathode and the anode is a key obstacle to their further development and application. Herein, we prepared TiNb 2 O 7 nanoparticles through a facile solvothermal method and annealing treatment. Then a homogeneous three-dimensional (3D) self-supported reduced graphene oxide (rGO)-coated TiNb 2 O 7 (TiNb 2 O 7 /rGO) nanocomposite was constructed by freeze-drying, followed by a high-temperature reduction, which demonstrates an enhanced pseudocapacitive lithium ions storage performance. Benefiting from the improved electrical conductivity, ultrashort ions diffusion paths, and 3D architecture, the TiNb 2 O 7 /rGO nanocomposite exhibits a high specific capacity of 285.0 mA h g -1 , excellent rate capability (73.6% capacity retention at 8 A g -1 ), and superior cycling stability. More importantly, quantitative kinetics analysis reflects that the capacity of TiNb 2 O 7 /rGO is mainly dominated by capacitive behavior, making it perfectly match with the capacitor-type activated carbon (AC) cathode. By using pre-lithiated TiNb 2 O 7 /rGO as anode material and AC as cathode material, a high-rate TiNb 2 O 7 /rGO//AC LIHC device can be fabricated, which delivers an ultrahigh energy density of 127 Wh kg -1 at the power density of 200 W kg -1 , a maximum power density of 10 kW kg -1 at the energy density of 56.4 Wh kg -1 , and durable service life., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Atomically thin 2D materials with high surface areas allow engineering its physical and chemical properties with help of combining or decorating with different classes of materials. The hybrid or heterostructure of two different atomically thin materials exhibits completely different chemical and electronics behavior as compared to its parent components. Here, MoS 2 quantum dots (QDs) are decorated onto ultrathin NiO nanosheets (NSs) by using a one-pot hydrothermal process. Uniformly dispersed MoS 2 QDs and ultrathin NiO NSs hybrid/heterostructure can provide more active reaction sites and accelerate the charge transfer rate. Benefiting from the heterointerfaces synergistic effect between MoS 2 QDs and NiO NSs, the MoS 2 QDs/NiO NSs electrode exhibits excellent electrocatalytic activity towards both hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). As a bifunctional electrocatalyst, the MoS 2 QDs/NiO NSs electrode has achieved highly efficient overall water splitting activity, which needs a low voltage of 1.61 V to deliver a 10 mA cm -2 with superior stability., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier Inc. All rights reserved.)

The development of white light-emitting LED (WLED) is now one of the important demands of present society due to its energy saving feature. However, in this work, an ingenious strategy has been employed to develop Forster resonance energy transfer (FRET) based and rare-earth material free luminescent duo (LD) for the generation of white light. A colloidal LD, consisting of nitrogen-doped graphene quantum dots (N-GQDs) and DCM dye (DCM@N-GQDs), is employed for demonstrating the FRET. The band-gap is engineered by nitrogen (N) doping in GQDs, and an energy transfer efficiency of ~30% for white light generation is attained. The widely tunable PL emission from blue to the red region has been obtained by changing the D-A ratio. Therefore, the present work has provided an alternate approach to widen the light emission band of a conventional laser dye, which is otherwise restricted within a limited region of the visible spectrum. FRET-based WLED (F-WLEDs) with colour rendering index of 70 and correlated colour temperature of 4690 K have also been fabricated. The F-WLED exhibits an emission overlapping of 56% with the solar spectrum (AM 1.5) in visible region, which is doubled in compared to that of a commercial WLED. The present report of rapid synthesis of highly luminescent N doped GQDs and the strategy used here for generation of FRET based colloidal DCM-GQDs luminescent duo may also be extended further with other suitable laser dyes for further widening as well as tuning the spectral range of light emissions of different commercially available laser dyes and GQDs for their different photonic applications., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Three-dimensional (3D) carbon-coated NiCo 2 S 4 nanowires structures doped with nitrogen are used for energy storage and conversions. The nitrogen doping in both the carbon layer and NiCo 2 S 4 nanowires enhances the electrochemical performances. Here, an easily scalable and simple temperature treatment has been used to decorate carbon-coated NiCo 2 S 4 nanowires with nitrogen doping (NC@NiCo 2 S 4 NWs) in 3D carbon architecture (carbon cloth). Benefiting from the nitrogen doping and ultrathin carbon layer, the as-prepared 3D NC@NiCo 2 S 4 NWs electrode exhibits the superior electrochemical performance for both asymmetric supercapacitor and electrocatalytic water splitting. An asymmetric supercapacitor assembled by the NC@NiCo 2 S 4 NWs and active carbon electrodes achieves a high energy density of 1.72 mWh cm -3 (68.87 Wh kg -1 ) under a power density of 10.63 mW cm -3 (425 W kg -1 ) with 90.1% retention of initial capacitance after 10,000 cycles. When employed as the electrocatalyst, the NC@NiCo 2 S 4 NWs show high activities towards electrocatalytic water splitting., (Copyright © 2019 Elsevier Inc. All rights reserved.)