Search

• Electrochemical performance was enhanced on the in situ synthesized MOF@MXene electrodes. • Morphology regulation was achieved through in-situ composition of 3D MOFs on 2D MXene. • Excellent specific capacitance of 1160.5 F g−1 at 1 A/g was obtained on Ni-MOF@MX 2. • Synergistic effects between MOF and MXene were responsible for the excellent performance. In this study, an in situ method was developed to synthesize a series of uniform 3D MOFs (Fe-, Cu-, Co-, Ni)-BTC@2D MXene (Ti 3 C 2 T x) composites, and the experimental results show that a typical sample of Ni-MOF@MX 2 exhibits the highest specific capacitance of 1160.5 F·g−1 and 736 F·g−1 at a current density of 1 A·g−1 and 20 A·g−1, respectively, which is 2.3 times higher than the value of 320 F·g−1 at a current density of 20 A·g−1 on the bare Ni-MOF, and particularly maintains significant cyclic stability after 10,000 cycles at a high current density of 20 A·g−1. The improved electrochemical performance is ascribed to the synergistic interaction between layered MXene and MOFs, which were evidenced by experiments and theoretical calculations. The Ni-MOF@MX 2//AC asymmetric supercapacitor (ASC) device demonstrates a maximum energy density of 48.2 Wh kg−1 at 750 W kg−1. It retains 94 % capacity after 10,000 cycles. Moreover, the value still maintained at 23.3 Wh·kg−1 when elevating power density to 15000 W·kg−1. This indicates that the obtained MOF@MXene composites are probably alternative materials for supercapacitor electrodes in energy storage. [ABSTRACT FROM AUTHOR]

• The simple & cost effective Cu 3 (PO 4) 2 was synthesized by the facile hydrothermal technique. • Due to the inductive effect of phosphate (PO 4)2− group, the Cu 3 (PO 4) 2 shows high operating discharge voltage widow of – 1.2 V. • The maximum specific capacitance of about 814 F/g was achieved due to the conversion type mechanism of copper. It also shows excelled cyclic stability of 100 % over 10,000 cycles without any structural distortion. • The fabricated symmetric device delivers remarkable power and energy density of 4.5 kW/kg and 31.5 Wh/kg, respectively. • The constructed device shows high capacitance retention 92 % without its sacrificing its columbic efficiency. The key to high-performing supercapacitors is their abundance, low cost, and ability to deliver high capacitance in a wide electrochemical window. A new class of phosphate-based polyanion material has been developed to deliver high capacitance via the effective utilization of their oxidation states. Cu 3 (PO 4) 2 was synthesized by the facile hydrothermal technique and delivers an ultra high specific capacitance of about 814 F/g with multiple discharge plateaus at a current density of 1 A/g within a voltage window ranging from 0.4 v to -1.2 V. This intriguing behavior is mainly due to the multi functional Cu while interacts with the electrolytic ions and also the inductive effect of a phosphate group (PO 4)2− contributes to a high discharge voltage of -1.2 V during charging and discharging process. It shows exceptional cyclic stability of 100 % over 10,000 cycles without sacrificing its coulombic efficiency and it is pertinent the structural stability of the system. The symmetric device was fabricated and delivered power density and energy density of 4.5 kW/kg and 31.5 Wh/kg, and also maintained excellent cyclic stability at 92 % with high reversibility of charged ions. This offers new insights into the high potential of using polyanion-type compounds as high-capacity materials for advanced energy storage systems. [Display omitted] [ABSTRACT FROM AUTHOR]

A P-doped Ni 0.5 Cu 0.5 Co 2 O 4 material with 1D/2D hierarchical structure on carbon cloth is successfully synthesized as the cathode material for high performance supercapacitor. [Display omitted] • A P-doped Ni 0.5 Cu 0.5 Co 2 O 4 material with 1D/2D hierarchical structure on carbon cloth is successfully synthesized. • The 9-P-Ni 0.5 Cu 0.5 Co 2 O 4 @CC electrode shows the specific capacity of 2872.1F/g. • The doping of P can effectively regulate the electronic structure and effectively improve the electrochemical performance of 9-NCCO@CC. • The supercapacitor delivers a high energy density of 71.57 Wh kg−1 at power density of 800 W kg−1. Multi-component synergy and controlled structural design can effectively tailor the electronic structure and multiply kinetic reactions, substantially enhancing the electrode material's performance. Herein, a novel P-doped Ni 0.5 Cu 0.5 Co 2 O 4 with a 1D/2D hierarchical nanostructure is synthesized in situ. The hierarchical architecture significantly improves the exposure of active areas and facilitates the diffusion of electrolyte ions. Theoretical calculations reveal that the P-doping is instrumental in fine-tuning the electronic structure, enhancing conductivity, and increasing the adsorption energy of OH−. These theoretical insights were corroborated by electrochemical measurements. Remarkably, the optimized P-Ni 0.5 Cu 0.5 Co 2 O 4 exhibited an ultrahigh capacitance of 2872.1 F g−1 at 1 A g−1, which is 1.58 times that of before phosphating (1810.6 F g−1). In addition, a hybrid supercapacitor based on 9-P-Ni 0.5 Cu 0.5 Co 2 O 4 was assembled, delivering an impressive energy density of 71.6 Wh kg−1 at a power density of 800 W kg−1. Furthermore, the device demonstrated outstanding cyclic performance, maintaining 87.73 % of its initial capacitance even after 10,000 cycles. This study not only showcases the superior performance of P-Ni 0.5 Cu 0.5 Co 2 O 4 but also provides a promising strategy for developing high-energy storage material. [ABSTRACT FROM AUTHOR]

Supercapacitors have attracted considerable attention because of their benefits in terms of high power density, rapid charge-discharge rates, and extended cycle life. Metal-organic framework materials (MOFs), known for their exceptionally high surface area and adjustable pore architectures, are extensively employed in the realm of energy conversion and storage. Nevertheless, the inadequate conductivity of MOF materials impedes their desirable electrochemical performances when employed as electrode materials in supercapacitors. We utilized a straightforward solvothermal technique to produce graphene-supported Cu/Mn-BTC metal-organic framework materials. These materials were then used as electrode materials for supercapacitors. Mn-BTC was effectively incorporated onto the surface and into the pores of Cu-BTC via solvothermal treatment. The incorporation of reduced graphene oxide (rGO) greatly increased the conductivity of MOF materials. In the three-electrode testing system, the graphene-supported Cu/Mn-BTC electrode material exhibited a specific capacitance of 362.2 C g−1 at the current density of 1 A g−1. Assembled into a symmetric supercapacitor, the novel material achieved a specific capacitance of 141.46 F g−1 at 1 A g−1, with a maximum energy density of 12.6 Wh kg−1 at a power density of 111.1 W kg−1. After 1000 charge-discharge cycles, the capacitance retention rate was 83.55 %. [Display omitted] • Innovative nanocomposites, i.e. rGO-supported dual metal organic frameworks, have been fabricated. • The novel material exhibits superior specific capacitance, rate capability, and long cycle life. • Symmetric supercapacitor device made up of this electrode material also exhibits better performances for practical application. [ABSTRACT FROM AUTHOR]

Cu doped SnS 2 /rGO composites are prepared by a one-step hydrothermal method. The obtained Cu doped SnS 2 /rGO composite shows a ultrathin lamellar structure, with quantum dots of SnS 2 anchored on reduced graphene oxide (rGO). According to the testing results from the three-electrode system indicate that the successful doping of Cu and the presence of rGO improve the electrochemical performance of SnS 2. The Cu doped SnS 2 /rGO composite exhibits a high specific capacitance of 387.27 F g−1 at 1 A g−1, which is almost seven times of that of pure SnS 2. It also performs well in cycling stability tests (95.2 % after 2000 cycles). The asymmetric supercapacitor also shows impressive energy and power densities. The excellent electrochemical performance reveals its potential application as a supercapacitor electrode material. • Cu doped SnS 2 /rGO electrode prepared by a simple one-step hydrothermal method. • Cu and rGO improved the electrical conductivity and electrochemical properties. • Composite electrode with high specific capacitance of 387.27 F g−1. • Preparation of supercapacitors with high energy density and power density. [ABSTRACT FROM AUTHOR]

• Tubular Cu 2 MoS 4 /MWCNTs were prepared as supercapacitor negative electrode material. • Appropriate MWCNTs addition significantly optimized the electrochemical performance. • CMS/MWCNTs-0.15@CC exhibits a highest specific capacitance of 219F g−1 at 0.5 A g−1. • The device with a voltage window of 1.8 V yields an energy density of 24.5 Wh kg−1 at 900 W kg−1. The ternary layered Cu 2 MoS 4 (CMS) has been proven to be a potential supercapacitor negative electrode material. However, its inherent low conductivity and limited diffusion dynamics usually result in unsatisfactory specific capacitance and rate performance. Therefore, hollow tubular CMS and CMS/MWCNTs-0.05, 0.15, 0.25 composite materials were prepared by a one-pot hydrothermal method in this work. The addition of MWCNTs improves the electrical conductivity and provides an efficient three-dimensional electronic transport network. Due to the smallest resistance and optimized porous structure with large surface area, CMS/MWCNTs-0.15@CC exhibits a highest specific capacitance (C s) of 219F g−1 at 0.5 A g−1, which is 2.45 times that of CMS@CC. The assembled Ni-Co-S@CC//CMS/MWCNTs-0.15@CC supercapacitor with a voltage window of 1.8 V yields a maximum energy density of 24.5 Wh kg−1 at 900 W kg−1. [ABSTRACT FROM AUTHOR]