High Power Na3V2(PO4)3@C/AC Bi-material Cathodes for Hybrid Battery-Capacitor Energy Storage Devices
High Power Na3V2(PO4)3@C/AC Bi-material Cathodes for Hybrid Battery-Capacitor Energy Storage Devices
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DOI：
10.1149/1945-7111/aba36d
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发表时间：
2020-01-08
影响因子：
3.9
通讯作者：
Majumder, S. B.
中科院分区：
文献类型：
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作者：
Akhtar, Mainul;Chang, Jeng-Kuei;Majumder, S. B.
报道了碳包覆磷酸钒钠/活性炭（NVP@C/AC）双材料电极的制备及其电化学性能。我们已经报道，与NVP@C或AC电极相比，双材料型NVP@C/AC阴极提供了优越的上级速率性能。通过详细的阻抗谱分析，我们证明了在双材料电极中观察到的协同效应与它们的电荷转移电阻（R-CT）的降低和Li（+）扩散系数（DLi+）随活性炭含量从0增加到0.60重量分数而增加密切相关。通过详细的循环伏安图分析，我们已经描绘了在各种速率条件下的法拉第和电容对双材料电极的总容量的贡献。对于这两种双材料，无论AC含量和速率如何，电容贡献主导总容量。NVP@C/AC 40的放电容量分别为67和40 mAh g（-1），在50和1000 mA g（-1）下测量的500次循环后的容量保持率分别超过93%和67%。这些双材料被证明是高功率密度锂钛氧化物（LTO）//NVP@C/AC混合电池-电容器（电池帽）能量存储设备的优异材料候选者。
We have reported the synthesis and electrochemical characteristics of carbon-coated sodium vanadium phosphate/activated carbon (NVP@C/AC) bi-material electrodes. We have reported that bi-material type NVP@C/AC cathodes offer superior rate performance as compared to either NVP@C or AC electrodes. Through a detailed impedance spectroscopy analyses, we demonstrated that the synergic effect observed in the bi-material electrodes correlates well with the lowering of their charge transfer resistances (R-CT) and the increase of Li(+)diffusion coefficient (DLi+) with the increase of activated carbon content from 0 to 0.60 weight fraction. Through a detailed cyclic voltammogram analyses we have delineated the faradaic and capacitive contribution towards the overall capacities of the bi-material electrodes at various rate conditions. For both these bi-materials, irrespective of the AC content and rate, capacitive contribution dominates the overall capacity. NVP@C/AC40 yields discharge capacities of 67 and 40 mAh g(-1)with capacity retention of more than 93% and 67% after 500 cycles measured at 50 and 1000 mA g(-1), respectively. These bi-materials are demonstrated to be excellent material candidates for high power density lithium titanium oxide (LTO)//NVP@C/AC hybrid battery-capacitor (bat-cap) energy storage devices.