Search

Metal–organic framework (MOF) is a promising electrochromic material due to its high specific surface area and tunable pore size, which can benefit the fast transportation of ion/charge. Here, a simple solvothermal deposition method for fabrication of Ni-MOF 74 electrochromic films on ITO is developed. It is found that the reaction temperature has played an important role in the morphology and electrochromic performance of as-prepared Ni-MOF 74 film. The film prepared at the optimized temperature exhibits the best electrochromic performance with a rapid switching speed (the coloration/bleaching time = 24.5/23.5 s). In addition, the optimized film displays a high optical contrast of 44.4% at 550 nm and can be stably switched for 650 cycles with

In this paper, MOF-derived N-doped porous carbon anchoring Sn4P3 (Sn4P3@NPC) composite is prepared via a low-temperature phosphidation reaction with SnO2@NPC composite as the precursor. The as-prepared Sn4P3@NPC composite exhibit a high stable capacity of 319 mAh g−1 at 0.1 A g−1 after 100 cycles and improved rate performance (the capacities of 365, 322, 260, 204, and 146 mAh g−1 at 0.1, 0.2, 0.5, 1, and 2 A g−1, respectively) for sodium ion batteries. The good electrochemical sodium storage performance of the Sn4P3@NPC composite anodes can be ascribed to the synergistic effect between porous N-doped carbon and high-active Sn4P3 nanoparticles.

Flower-like MoS2 supported on three-dimensional graphene aerogel (MoS2/GA) composite has been prepared by a facile hydrothermal method followed by subsequent heat-treatment process. Each of MoS2 microflowers is surrounded by the three-dimensional graphene nanosheets. The MoS2/GA composite is applied as an anode material of sodium-ion batteries (SIBs) and it exhibits high initial discharge/charge capacities of 562.7 and 460 mAh g−1 at a current density of 0.1 A g−1 and good cycling performance (348.6 mAh g−1 after 30 cycles at 0.1 A g−1). The good Na+ storage properties of the MoS2/GA composite could be attributed to the unique structure which flower-like MoS2 are homogeneously and tightly decorated on the surface of three-dimensional graphene aerogel. Our results demonstrate that as-prepared MoS2/GA composite has a great potential prospect as anodes for SIBs.

The fast development of supercapacitors inspires a growing interest in inexpensive super-capacitive electrode material with high performance. Herein, we develop a Rone step method for preparing Cu3P nanocrystals by direct low-temperature phosphorization treatment of commercial copper powder. As a super-capacitive electrode material, for the first time, Cu3P nanocrystals exhibit outstanding electrochemical rate performance (318.5 F g−1 at 400 mV s−1; 169.2 F g−1 at 50 A g−1) and excellent cycling stability with no loss of specific capacitance at 10 A g−1 for 10,000 cycles. The presented synthesis method opens up a facile and large-scale approach to explore high-performance and low-cost Cu3P electrodes for supercapacitors.

Three-dimensional fabricated Fe3O4 quantum dots/graphene aerogel materials (Fe3O4 QDs/GA) were obtained from a facile hydrothermal strategy, followed by a subsequently heat treatment process. The Fe3O4 QDs (2–5 nm) are anchored tightly and dispersed uniformly on the surface of three-dimensional GA. The as-prepared anode materials exhibit a high reversible capacity of 1078 mAh g−1 at a current density of 100 mA g−1 after 70 cycles in lithium-ion batteries (LIBs) system. Moreover, the rate capacity still remains 536 mAh g−1 at 1000 mA g−1. The enhanced electrochemical performance is attributed to that the GA not only acts as a three-dimensional electronic conductive matrix for the fast transportation of Li+ and electrons, but also provides with double protection against the aggregation and pulverization of Fe3O4 QDs during cycling. Apparently, the synergistic effects of the three-dimensional GA and the quantum dots are fully utilized. Therefore, the Fe3O4 QDs/GA composites are promising materials as advanced anode materials for LIBs.

High-quality monodisperse multiporous hierarchical micro/nanostructured ZnCo2O4 microspheres have been fabricated by calcinating the Zn1/3Co2/3CO3 precursor prepared by urea-assisted solvothermal method. The as-prepared products are characterized by X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), high-resolution transmission electron microscopy (HRTEM), and Brunauer-Emmett-Teller (BET) measurement to study the crystal phase and morphology. When tested as anode material for lithium ion batteries, the multiporous ZnCo2O4 microspheres exhibit an initial discharge capacity of 1,369 mAh g−1 (3,244.5 F cm−3) and retain stable capacity of 800 mAh g−1 (1,896 F cm−3) after 30 cycles. It should be noted that the good electrochemical performances can be attributed to the porous structure composed of interconnected nanoscale particles, which can promote electrolyte diffusion and reduce volume change during discharge/charge processes. More importantly, this ZnCo2O4 3D hierarchical structures provide a large number of active surface position for Li+ diffusion, which may contribute to the improved electrochemical performance towards lithium storage.

The cooling rate after annealing treatment was proved to be important for the structure and electrochemical performances of the layered oxide 0.3Li2MnO3 · 0.7LiNi0.5Mn0.5O2 material, which has been synthesized using a sol–gel method. Powder X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), nondestructive nano-computed tomography (nano-CT), and Brunauer-Emmett-Teller (BET) surface area measurement were used to characterize the structure and micromorphology of the material. It was demonstrated that the material quenched by liquid nitrogen (AN-material) showed less defects in structure and larger specific surface area than the material cooled naturally (AF-material). Electrochemical measurement showed that the AN-material exhibited better electrochemical performance as cathode candidate for lithium-ion batteries. The initial discharge capacity and coulombic efficiency reached 277.4 mAh g−1 and 84.1 % for AN-material, while 257.1 mAh g−1 and 78.4 % for AF-material. In addition, the AN-material also exhibited lower charge transfer resistance than AF-material.