Search

Zn-ion hybrid supercapacitors (ZSC) have shown great potential as energy storage devices as they incorporate the merits of rechargeable batteries and supercapacitors. However, the poor bendability, unsatisfied energy density and cycling stability are still challenging the practical application of ZSC. Herein, Zn-doped MnO 2 nanowires (Zn-MnO 2) binder-free cathodes is synthesized with the aid of a one-step hydrothermal approach, which improves the lattice distortion caused by Zn hydrate ions and provided rich ion transport path. The Zn-MnO 2 cathode was assembled with the active carbon (AC) anode into an axial ZSC, achieving a surface capacitance of 1300 mF cm−2 and an energy density of 722.2 μWh cm−2 at power density of 1.99 mW cm−2. After 20,000 charge/discharge cycles, a capacity retention rate of 83.75% and a coulombic efficiency of 100% were achieved, indicating excellent cycle stability of present device. In addition, this axial ZSC reveals exquisite mechanical flexibility and electrochemical stability, enabling continuously power smartphones under bending conditions. Present work suggests that ZSC devices based on Zn-MnO 2 have excellent doable for business energy storage devices. • A axial ZSC was designed with Zn-doped MnO 2 cathode and carbon material anode. • The axial structure improves the flexibility and stability of the ZSC device. • The ZSC device displays high energy density (722.2 μWh cm−2). • The fiber-type device can be applied as wearable bracelet power supply device. [ABSTRACT FROM AUTHOR]

Nickel-Cobalt layered double hydroxide (NiCo-LDH) nanosheets have the advantages of large interlayer spacing, adjustable structure, and high theoretical capacity, which has attracted extensive attention. However, the poor conductivity and structural instability limit their application in electrode materials. Herein, a high-performance all-solid-state asymmetric supercapacitor (ASC) is designed with AC as the anode and Ni 3 S 2 @NiCo-LDH as the cathode. The open Ni 3 S 2 @NiCo-LDH cross-linked nanosheets arrays are uniformly arranged on the Ni foam (NF), which not only increases the sufficient contact area between electrode and electrolyte, but also facilitates the rapid transfer of electrons. Therefore, the assembled ASC exhibits high area-specific capacitance of 1267.2 mF cm−2 at 5 mA cm−2, high energy density of 450.60 μW h cm−2 at the power density of 3.99 mW cm−2, and excellent cyclic stability with 85.2 % capacity retention over 5000 cycles. This work demonstrates the feasibility of the cross-linked nanosheets arrays of Ni 3 S 2 @NiCo-LDH on NF, which shows great potential as electrode for novel energy storage devices. • Ni 3 S 2 @NiCo-LDH/NF and AC/NF are prepared as electrodes. • The cross-linked nanosheet array structure improves the electrical conductivity and specific capacitance of electrodes. • The Ni 3 S 2 @NiCo-LDH composites deliver a high energy density for the all-solid-state asymmetric supercapacitor. • The device exhibits great potential as high-performance energy storage devices. [ABSTRACT FROM AUTHOR]

• NDs are uniformly dispersed in the matrix by a surface modification strategy. • NDs are intimately contacted with the matrix, forming stable, low-indexed interfaces. • A high tensile strength of 741.1 MPa was achieved for 0.8 vol% ND/2024Al composite. • The strengthening mechanisms of ND/2024Al composites are clarified. Poor dispersion of nanodiamonds (NDs) is the bottleneck to exploit their intrinsically excellent properties in metal matrix composites (MMCs). In this study, a strategy of surface modification was developed to uniformly disperse ND particles into 2024 aluminum alloy. Microstructure observations showed that individual NDs are closely contacted with the matrix, forming reaction-free interfaces. Consequently, a high-strength 0.8 vol% ND/2024Al composite with an ultimate tensile strength of 741.0 MPa is developed. Theoretical and experimental measurements prove that the strength improvement of ND/2024Al composite is mainly attributed to the Orowan strengthening, thermal mismatch strengthening and grain refinement strengthening. This work demonstrates the effective application of NDs as a reinforcement for MMCs towards high-specific-strength materials. [ABSTRACT FROM AUTHOR]