Bolei Shen

Fabrication of WS2-nanoflowers@rGO composite as an anode material for enhanced electrode performance in lithium-ion batteries

In this paper, we descried a simple method to fabricate three-dimensional (3D) composite materials, WS2-nanoflowers @ reduced graphene oxide (WS2-NF@rGO), in which rGO crossed-link the isolated WS2-NF to construct a 3D conductive network and provided protection against the volume changes of WS2 during electrochemical processes simultaneously. This unique structure of the WS2-NF@rGO composite could not only promote both ion and electron diffusion, but also enhance the electrode stability, thus obtaining a high-capacity and long-cycle anode material for lithium-ion batteries. As a result, the WS2-NF@rGO exhibited a reversible capacity of 730mAhg-1 after 150 cycles at 100mAg-1 and maintained a capacity of higher than 260mAhg-1 at 2Ag-1, thus exhibiting great potential as an anode material for lithium storage.

Exploration of Na7Fe4.5(P2O7)4 as a cathode material for sodium-ion batteries

A novel Na7Fe4.5(P2O7)4 compound was fabricated as a cathode for sodium-ion batteries by a mechanical milling assisted solid state method for the first time. The as-prepared material exhibits superior electrochemical performance based on half-cell testing. After uniform carbon coating, it exhibits lower electrochemical polarization, better conductivity and faster sodium ion diffusion kinetics. Benefiting from these advantages, the Na7Fe4.5(P2O7)4 was endowed with higher charge–discharge capacity, better cycle life and outstanding rate performance. The high rate capability and good cyclability of this material in non-aqueous electrolytes are advantageous for low-cost and safe battery systems.

Sodium-rich ferric pyrophosphate cathode for stationary room-temperature sodium-ion batteries

In this article, carbon-coated Na3.64Fe2.18(P2O7)2 nanoparticles (∼10 nm) were successfully synthesized via a facile sol-gel method and employed as cathode materials for sodium-ion batteries. The results show that the carbon-coated Na3.64Fe2.18(P2O7)2 cathode delivers a high reversible capacity of 99 mAh g-1 at 0.2 C, outstanding cycling life retention of 96%, and high Coulomb efficiency of almost 100% even after 1000 cycles at 10 C. Furthermore, the electrochemical performances of full batteries consisting of carbon-coated Na3.64Fe2.18(P2O7)2 nanoparticles as the cathode and commercialized hard carbon as the anode are tested. The full batteries exhibit a reversible capacity of 86 mAh g-1 at 0.5 C and capacity retention of 80% after 100 cycles. Therefore, the above-mentioned cathode is a potential candidate for developing inexpensive sodium-ion batteries in large-scale energy storage with long life.

Improving the Performance of Hard Carbon//Na3V2O2(PO4)2F Sodium-Ion Full Cells by Utilizing the Adsorption Process of Hard Carbon

Hard carbon has been regarded as a promising anode material for Na-ion batteries. Here, we show, for the first time, the effects of two Na+ uptake/release routes, i.e., adsorption and intercalation processes, on the electrochemical performance of half and full sodium batteries. Various Na+-storage processes are isolated in full cells by controlling the capacity ratio of anode/cathode and the sodiation state of hard carbon anode. Full cells utilizing adsorption region of hard carbon anode show better cycling stability and high rate capability compared to those utilizing intercalation region of hard carbon anode. On the other hand, the intercalation region promises a high working voltage full cell because of the low Na+ intercalation potential. We believe this work is enlightening for the further practical application of hard carbon anode.

An iron hydroxyl phosphate microoctahedron catalyst as an efficient peroxidase mimic for sensitive and colorimetric quantification of H2O2 and glucose

A colorimetric assay for H2O2 that is based on the use of iron hydroxyl phosphate (Fe3(PO4)2(OH)2) microoctahedrons, which are shown to be efficient peroxidase mimics, has been described. The microoctahedrons were prepared via a one-pot hydrothermal method. They catalyze H2O2 reduction and 3,3′,5,5′-tetramethylbenzidine (TMB) oxidation to produce a blue product whose color can be observed visually and measured using spectrophotometry, best at 652 nm. The method was applied for the quantification of H2O2 with a limit of detection (LOD) of 0.17 μM. The scope of the method was further extended to the determination of glucose by using the enzyme glucose oxidase which catalyzes glucose oxidation to produce gluconic acid and H2O2 which was quantified as described above. The response is linear in the 5–100 μM glucose range, and the LOD is 1.2 μM. This work not only reports a new kind of peroxidase mimic, but also develops a simple, robust and sensitive colorimetric sensing platform for H2O2 and glucose detection in biomedicine and food industry.