Ultra-high-rate pseudocapacitive energy storage in two-dimensional transition metal carbides
Ultra-high-rate pseudocapacitive energy storage in two-dimensional transition metal carbides
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DOI：
10.1038/nenergy.2017.105
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发表时间：
2017-08-01
期刊：
影响因子：
56.7
通讯作者：
Gogotsi, Yury
中科院分区：
文献类型：
--
作者：
Lukatskaya, Maria R.;Kota, Sankalp;Gogotsi, Yury
使用快速表面氧化还原存储（赝电容）机制可以使设备存储比双电层电容器（EDLC）多得多的能量，并且与电池不同，可以非常快速地存储能量。然而，由于它们的低固有电子和离子电导率，很少赝电容过渡金属氧化物可以提供高功率容量。在这里，我们证明了二维过渡金属碳化物（MXenes）可以以超过常规EDLC的速率工作，但仍然提供比碳、导电聚合物或过渡金属氧化物更高的体积和面积电容。我们将两种不同的设计应用于MXene电极架构，其具有对氧化还原活性位点的改进的离子可及性。大孔Ti（3）C（2）Tx MXene膜在10 Vs（-1）的扫描速率下提供高达210 F g（-1），超过已知的最好的碳超级电容器。相比之下，我们表明MXene水凝胶能够提供类似于1，500 F cm（-3）的体积电容，达到以前无与伦比的RuO 2体积性能。
The use of fast surface redox storage (pseudocapacitive) mechanisms can enable devices that store much more energy than electrical double-layer capacitors (EDLCs) and, unlike batteries, can do so quite rapidly. Yet, few pseudocapacitive transition metal oxides can provide a high power capability due to their low intrinsic electronic and ionic conductivity. Here we demonstrate that two-dimensional transition metal carbides (MXenes) can operate at rates exceeding those of conventional EDLCs, but still provide higher volumetric and areal capacitance than carbon, electrically conducting polymers or transition metal oxides. We applied two distinct designs for MXene electrode architectures with improved ion accessibility to redox-active sites. A macroporous Ti(3)C(2)Tx MXene film delivered up to 210 F g(-1) at scan rates of 10Vs(-1), surpassing the best carbon supercapacitors known. In contrast, we show that MXene hydrogels are able to deliver volumetric capacitance of similar to 1,500 F cm(-3) reaching the previously unmatched volumetric performance of RuO2.