4 research outputs found

    A Highly Reversible Low-Cost Aqueous Sulfur–Manganese Redox Flow Battery

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    Redox flow batteries are promising energy storage technologies. Low-cost electrolytes are the prerequisites for large-scale energy storage applications. Herein, we describe an ultra-low-cost sulfur–manganese (S–Mn) redox flow battery coupling a Mn2+/MnO2(s) posolyte and polysulfide negolyte. In addition to the intrinsically low cost active materials, the polysulfide negolyte removes the long-unresolved metal dendrite issue of metal–Mn batteries (e.g., Zn–Mn2+/MnO2(s) batteries), enabling substantially improved cycling stability at a high areal capacity (50–100 mAh cm–2). Due to the low cost of both sulfur and manganese species, this system promises an ultralow electrolyte cost of $11.00 kWh–1 (based on achieved capacity). This work broadens the horizons of aqueous manganese-based batteries beyond metal–manganese chemistry and offers a practical route for low-cost and long-duration energy storage applications

    Modified Separator Using Thin Carbon Layer Obtained from Its Cathode for Advanced Lithium Sulfur Batteries

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    The realization of a practical lithium sulfur battery system, despite its high theoretical specific capacity, is severely limited by fast capacity decay, which is mainly attributed to polysulfide dissolution and shuttle effect. To address this issue, we designed a thin cathode inactive material interlayer modified separator to block polysulfides. There are two advantages for this strategy. First, the coating material totally comes from the cathode, thus avoids the additional weights involved. Second, the cathode inactive material modified separator improve the reversible capacity and cycle performance by combining gelatin to chemically bond polysulfides and the carbon layer to physically block polysulfides. The research results confirm that with the cathode inactive material modified separator, the batteries retain a reversible capacity of 644 mAh g<sup>–1</sup> after 150 cycles, showing a low capacity decay of about 0.11% per circle at the rate of 0.5<i>C</i>

    Mesopore- and Macropore-Dominant Nitrogen-Doped Hierarchically Porous Carbons for High-Energy and Ultrafast Supercapacitors in Non-Aqueous Electrolytes

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    Non-aqueous electrolytes (e.g., organic and ionic liquid electrolytes) can undergo high working voltage to improve the energy densities of supercapacitors. However, the large ion sizes, high viscosities, and low ionic conductivities of organic and ionic liquid electrolytes tend to cause the low specific capacitances, poor rate, and cycling performance of supercapacitors based on conventional micropore-dominant activated carbon electrodes, limiting their practical applications. Herein, we propose an effective strategy to simultaneously obtain high power and energy densities in non-aqueous electrolytes via using a cattle bone-derived porous carbon as an electrode material. Because of the unique co-activation of KOH and hydroxyapatite (HA) within the cattle bone, nitrogen-doped hierarchically porous carbon (referred to as NHPC–HA/KOH) is obtained and possesses a mesopore- and macropore-dominant porosity with an ultrahigh specific surface area (2203 m<sup>2</sup> g<sup>–1</sup>) of meso- and macropores. The NHPC–HA/KOH electrodes exhibit superior performance with specific capacitances of 224 and 240 F g<sup>–1</sup> at 5 A g<sup>–1</sup> in 1.0 M TEABF<sub>4</sub>/AN and neat EMIMBF<sub>4</sub> electrolyte, respectively. The symmetric supercapacitor using NHPC–HA/KOH electrodes can deliver integrated high energy and power properties (48.6 W h kg<sup>–1</sup> at 3.13 kW kg<sup>–1</sup> in 1.0 M TEABF<sub>4</sub>/AN and 75 W h kg<sup>–1</sup> at 3.75 kW kg<sup>–1</sup> in neat EMIMBF<sub>4</sub>), as well as superior cycling performance (over 89% of the initial capacitance after 10 000 cycles at 10 A g<sup>–1</sup>)
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