Ordered mesoporous α-MoO3 with iso-oriented nanocrystalline walls for thin-film pseudocapacitors
Ordered mesoporous α-MoO3 with iso-oriented nanocrystalline walls for thin-film pseudocapacitors
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DOI：
10.1038/nmat2612
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发表时间：
2010-02-01
期刊：
影响因子：
41.2
通讯作者：
Dunn, Bruce
中科院分区：
文献类型：
--
作者：
Brezesinski, Torsten;Wang, John;Dunn, Bruce
电容储能与其他类型的电化学储能的区别在于充电时间短，并且能够提供比电池更多的电力。这种技术的一个关键限制是它的低能量密度，并且由于这个原因，在探索其中法拉第机制提供增加的能量存储水平的赝电容材料方面存在相当大的兴趣。在这里，我们表明，等取向的α-MoO3的介孔膜的电容电荷存储性能是上级的介孔无定形材料或非多孔结晶MoO3。尽管结晶和无定形介孔材料都显示氧化还原赝电容，但等取向的层状结晶域使锂离子能够插入到α-MoO3的货车德瓦尔斯间隙中。我们建议，这种额外的贡献来自嵌入赝电容，发生在相同的时间尺度上的氧化还原赝电容。其结果是增加的电荷存储容量，而不损害充电/放电动力学在介孔晶体MoO3。
Capacitive energy storage is distinguished from other types of electrochemical energy storage by short charging times and the ability to deliver significantly more power than batteries. A key limitation to this technology is its low energy density and for this reason there is considerable interest in exploring pseudocapacitive materials where faradaic mechanisms offer increased levels of energy storage. Here we show that the capacitive charge-storage properties of mesoporous films of iso-oriented alpha-MoO3 are superior to those of either mesoporous amorphous material or non-porous crystalline MoO3. Whereas both crystalline and amorphous mesoporous materials show redox pseudocapacitance, the iso-oriented layered crystalline domains enable lithium ions to be inserted into the van der Waals gaps of the alpha-MoO3. We propose that this extra contribution arises from an intercalation pseudocapacitance, which occurs on the same timescale as redox pseudocapacitance. The result is increased charge-storage capacity without compromising charge/discharge kinetics in mesoporous crystalline MoO3.