【摘要】 锂-硫电池因其较高的理论质量能量密度而广为人知.然而,与以重质过渡金属氧化物作为正极材料的传统锂离子电池相比,锂-硫较低的体积能量密度是其实际应用的瓶颈.此外,硫单质通常与轻质导电碳基底材料复合,以实现其电化学循环稳定性.这使得锂-硫电池实际体积能量密度更低.本文通过静电纺丝方法制备了铁酸镍纳米纤维,并将其用作新型载体材料.铁酸镍不仅可以化学固定多硫化锂,提高硫电极的循环稳定性,而且有利于硫/铁酸镍的高体积比容量.测试结果显示,相比于硫/碳纳米管复合材料,硫/铁酸镍复合材料具有更高的振实密度;在0.1 C倍率充放电时,以复合材料为活性物质计算,该复合材料的初始体积比容量为1281.7 mA h cm^-3,是硫/碳纳米管复合材料容量的1.9倍.本工作提出以高振实密度的金属铁氧体材料来实现硫正极的高稳定性和高体积比容量,这一新策略有助于实现锂-硫电池的高体积能量密度.更多还原

【Abstract】 Low volumetric energy density is a bottleneck for the application of lithium-sulfur（Li-S） battery. The lowdensity sulfur cooperated with the light-weight carbon substrate realizes electrochemical cycle stability, but leads to worse volumetric energy density. Here, nickel ferrite（NiFe₂O₄） nanofibers as novel substrate for sulfur not only anchor lithium polysulfides to enhance the cycle stability of sulfur cathode, but also contribute to the high volumetric capacity of the S/nickel ferrite composite. Specifically, the S/nickel ferrite composite presents an initial volumetric capacity of 1,281.7 mA h cm^-3-compositeat 0.1 C rate, 1.9 times higher than that of S/carbon nanotubes, due to the high tap density of the S/nickel ferrite composite.更多还原