Shasha Zheng

Facile synthesis of an accordion-like Ni-MOF superstructure for high-performance flexible supercapacitors

Metal–organic frameworks have received increasing attention as promising electrode materials in supercapacitors. In this study, we have successfully synthesized a novel accordion-like Ni-MOF superstructure ([Ni3(OH)2(C8H4O4)2(H2O)4]·2H2O), for the first time, and used it as an electrode material for supercapacitors. The supercapacitors with the novel electrode exhibited excellent electrochemical performance. For example, the accordion-like Ni-MOF electrode showed specific capacitances of 988 and 823 F g−1 at current densities of 1.4 and 7.0 A g−1, respectively, while maintaining outstanding cycling stability (capacitance retention of 96.5% after 5000 cycles at a current density of 1.4 A g−1). More importantly, the accordion-like Ni-MOF and activated carbons were assembled into a high-performance flexible solid-state asymmetric supercapacitor with a specific capacitance of 230 mF cm−2 at a current density of 1.0 mA cm−2. The cycle test showed that the device can offer 92.8% capacity of the initial capacitance at 5.0 mA cm−2 after 5000 cycles with little decay. The maximum energy density of the device can achieve 4.18 mW h cm−3 and the maximum power density can also achieve 231.2 mW cm−3.

Facile synthesis of ultrathin Ni-MOF nanobelts for high-efficiency determination of glucose in human serum

Ultrathin Ni-MOF nanobelts, [Ni20(C5H6O4)20(H2O)8]·40H2O(Ni-MIL-77 NBs), were synthesized by a facile one-pot solution process and can be used as an efficient catalyst electrode for glucose oxidation under alkaline conditions. Electrochemical measurements demonstrate that the NB/GCE, when used as a non-enzymatic glucose sensor, offers superior analytical performances with a wide linear range (from 1 μM to 500 μM), a low detection limit (0.25 μM, signal-to-noise = 3), and a response sensitivity of 1.542 μA mM-1 cm-2. Moreover, it can also be applied for glucose detection in human blood serum with the relative standard deviation (RSD) of 7.41%, showing the high precision of the sensor in measuring real samples.

Fabrication of Metal Molybdate Micro/Nanomaterials for Electrochemical Energy Storage

Currently, metal molybdates compounds can be prepared by several methods and are considered as prospective electrode materials in many fields because the metal ions possess the ability to exist in several oxidation states. These multiple oxidation states contribute to prolonging the discharge time, improving the energy density, and increasing the cycling stability. The high electrochemical performance of metal molybdates as electrochemical energy storage devices are discussed in this review. According to recent publications and research progress on relevant materials, the investigation of metal molybdate compounds are discussed via three main aspects: synthetic methods, material properties and measured electrochemical performance of these compounds as electrode materials. The recent progress in general metal molybdate nanomaterials for LIBs and supercapacitors are carefully presented here.

Dual anode materials for lithium- and sodium-ion batteries

Currently, the application of new energy conversion and storage technologies is urgent in order to meet the increasing requirements for energy. Rechargeable batteries are universal devices, and among them, the use of lithium-ion batteries and sodium-ion batteries is particularly extensive, and they show great potential. Thus, it is necessary to find suitable anode materials that have the capability of playing a dual storage role in both lithium-ion batteries and sodium-ion batteries. This review summarizes and evaluates recent progress in the research on dual anode materials for lithium-ion batteries and sodium-ion batteries in detail. The morphologies, synthesis schemes, and electrochemical performances of these materials and future prospects in this field are also included.

Ultrathin two-dimensional cobalt–organic framework nanosheets for high-performance electrocatalytic oxygen evolution

Ultrathin two-dimensional cobalt–organic framework (Co–MOF) nanosheets [Co2(OH)2BDC, BDC = 1,4-benzenedicarboxylate] with good catalytic activity for the oxygen evolution reaction were synthesized by a simple surfactant-assisted hydrothermal method. The resulting material shows a low overpotential of 263 mV at 10 mA cm−2 and a Tafel slope of 74 mV dec−1 in 1.0 M KOH. The morphology and properties of the material before and after electrocatalysis did not change significantly over a long period of time and it maintained electrochemical stability for 12 000 s. The unsaturated CoII active center on the surface of the ultrathin two-dimensional cobalt–organic framework nanosheets enhances their oxygen evolution reaction performance. These results are significantly superior to most of the previously reported transition metal–organic framework or metal oxide electrocatalysts. We believe that the ultrathin two-dimensional metal–organic framework nanosheets synthesized by this simple process will be widely used in future energy conversion devices.