MXene (MX) is a capable material for future generation supercapacitor devices. But, the attraction between active functional groups and hydrogen bonds on the surface of MX make the interlayer agglomerate obviously. In this work, we present a ZnCo-MOF (ZCM) derived ZnCo2O4 (ZCO) particles to adsorb on the (MX) nanosheets and form a mesoporous structure which may provide the flexible ion diffusion pathways. The as obtained MXene@ZnCo2O4 (MX@ZCO) composite is investigated using XRD, XPS, HRTEM, FESEM, and nitrogen adsorption and desorption isotherm analysis. The ZCO particles not only provide activation sites for free movement of charges but also help to avoid the agglomeration of MX nanosheets. Benefitted from this novel composite structure, MX@ZCO holds a great specific capacity of 260 mAh g−1 at the current density of 1 mA g−1. Further, the MX@ZCO electrode exhibits a good cyclic stability of 78.9% even after 5000 cycles at the current density of 10 mA g−1, which can be ascribed to excellent electronic conductivity and short ion transport path. Furthermore, the fabricated aqueous HSC device with MX@ZCO/NF as a positive electrode and AC/NF as a negative electrode revealed a high energy density of 63.8 Wh kg−1 at power density of 3512.2 W kg−1, along with the outstanding capacitance retention of 91.3% even after 15,000 GCD cycles. This work offers an excellent approach for the preparation of MX and ZCO composite material as an electrode for hybrid supercapacitors.

Strong reddish-orange-emitting (Sr,Ba)2YTaO6:Eu3+ phosphors were synthesized via a facile solid-state reaction. Due to the occupation of Y3+ ions in the high symmetry (Oh) sites as an inversion symmetry site, the 5D0 → 7F1 magnetic dipole transition peak was dominant in the (Sr,Ba)2YTaO6:Eu3+ phosphors under the charge transfer band excitation. Both Sr2YTaO6:Eu3+ (SYTO:Eu3+) and Ba2YTaO6:Eu3+ (BYTO:Eu3+) phosphors exhibited good thermal stability and quantum yield. Their luminescence sensing performances (relative sensing sensitivity) were determined to be 0.18% K−1 (BYTO:0.1Eu3+) and 0.13% K−1 (SYTO:0.1Eu3+) with the aid of the Struck and Fonger models. Furthermore, novel deep ultraviolet-excited phosphors-based polydimethylsiloxane flexible light-emitting films were fabricated for anti-counterfeiting applications. Consequently, this work reveals that the strong reddish-orange-emitting (Sr,Ba)2YTaO6:Eu3+ phosphors are suitable for dual-functional applications including luminescence lifetime thermometry and flexible anti-counterfeiting labels.

Nowadays, metal–organic framework-derived (MOF-D) materials are auspicious in various research areas due to their beneficial traits of diverse structural features, large surface area, and high porous nature. Herein, we report the MOF-D nickel–cobalt terephthalate hydroxides (Ni-Co THs) via a one-pot solvothermal approach without further annealing. Direct growth of active materials on conductive substrates (e.g., nickel foam (NF)) can potentially eliminate the use of sluggish and non-conductive binders, leading to enhanced redox chemistry with commercial-level mass loading (8–10 mg cm−2). All the binder-free MOF-D Ni-Co TH electrodes demonstrated excellent areal capacities at the same current density of 3 mA cm−2. Among them, the Ni-Co TH-160/9h electrode delivered a superior areal capacity/specific capacity of 2087 µAh cm−2/200.68 mAh g−1 at 3 mA cm−2, together with outstanding cycling retention of 100 % after 20,000 charge–discharge cycles. The achieved ultrahigh performance is ascribed to the synergistic properties of Ni-Co THs, three-dimensional porous NF, and morphological structures. Utilizing the charge storage performance of the Ni-Co TH-160/9h electrode, an electrochemical cell (ECC) was assembled. The as-assembled ECC delivered good areal capacity (1678.6 µAh cm−2), energy density (1.3 mWh cm−2), and power density (48.6 mW cm−2) with outstanding cycling performance (35,000 cycles (99.9 %)). Also, the ECC verified its energy storage properties by powering various portable electronic appliances.

Molybdenum disulfide (MoS2) has attracted great attention as a promising material for sodium (Na)-ion batteries (SIBs) due to its high theoretical capacity and unique layered structure. However, the intrinsic poor electrical conductivity and uncontrollable volume change of the pristine MoS2 during the ion insertion/extraction process result in its low rate performance and rapid capacity fading. Considering that the migration path length of the ion determines its diffusion time, shortening it can further increase the diffusion rate, thereby realizing fast Na ion storage. Herein, we prepare an interconnected network heterostructure consisting of small-sized MoS2 anchored on nitrogen-doped MXene substrates (MXene-MoS2). The as-prepared MXene-MoS2 heterostructure not only enhances the electrical conductivity and structural stability of the electrode materials but also reduces the Na ion diffusion length to achieve rapid Na ion transport kinetics. Meanwhile, the robust heterointerface guarantees fast and unimpeded electron transfer channels, thereby improving the electrochemical reaction kinetics. As a consequence, the MXene-MoS2 delivers an excellent reversible capacity of 315 mAh g−1 at 0.2 A g−1 and 220.0 mAh g−1 after 1000 cycles at 2.0 A g−1. This study may provide the possibility for the practical application of the MXene-MoS2 as a SIB anode.

Exploiting high-performance and efficient electrode materials is important for stimulating the energy density of hybrid supercapacitors. However, it is a big challenge to fabricate a well-ordered amorphous/crystalline hetero-phase with hydroxides/oxides for high energy storage. Herein, the fabrication of hetero-phase arrangement with amorphous nickel-manganese hydroxide (NiMn) nanosheets (NSs) as a shell and crystalline nickel-molybdenum hydrate oxide (NiMo) nanorods (NRs) as a core (i.e., NiMo NRs@NiMn NSs architecture) is reported. With the advantages of the NSs wrapped NRs, tri-metallic composite electrode demonstrates superior areal capacity and excellent cycling retention. Moreover, the NiMo NRs@NiMn NSs are prepared at various reaction temperatures (i.e., 140, 160, and 180 °C) to study the influence on the morphology and electrochemical performance. The synergistic behavior of the core–shell design (prepared at 160 °C) demonstrates a maximum areal capacity of 979.2 μAh/cm2 at 5 mA/cm2 which is higher than the other electrodes as well as good cycling stability (10,000 cycles). Additionally, a pouch-like hybrid cell (PHC) assembled with NiMo NRs@NiMn NSs-160 and activated carbon electrodes exhibits a maximum areal capacity of 500.60 µAh/cm2 (at 5 mA/cm2) with excellent energy and power densities of 392.9 μWh/cm2 and 4828.3 μW/cm2, respectively. Especially, the PHC reveals a long-life stability with 99.1 % retention after 10,000 cycles. The practicability of PHC is demonstrated by operating various portable electronic devices.