Stable high-voltage aqueous pseudocapacitive energy storage device with slow self-discharge
Stable high-voltage aqueous pseudocapacitive energy storage device with slow self-discharge
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DOI：
10.1016/j.nanoen.2019.103961
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发表时间：
2019-10-01
期刊：
影响因子：
17.6
通讯作者：
Gogotsi, Yury
中科院分区：
文献类型：
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作者：
Avireddy, Hemesh;Byles, Bryan W.;Gogotsi, Yury
我们展示了一种在醋酸钾基盐中水电解液中的不对称超级电容器，其中二维碳化钛Mxene和氧化锰分别作为负极和正极材料。使用盐中水电解液使组装的非对称器件的电池电压最高可达2.2V，这克服了水溶液假电容器中电池电压有限的问题(1.2-1.4V)。该电池在5到100 mV的S(-1)电压范围内表现出优异的倍率性能(类似于48%)，在10,000次充放电循环(1Ag(-1))和2.2V的25h保持电压下具有良好的稳定性(类似于93%)，与使用活性碳电极和氟化亚胺基盐中水电解液设计的不对称超级电容器的性能相比具有竞争力。此外，我们的器件具有较慢的自放电速度，体积能量密度比活性碳基超级电容器高32%，在体积能量密度非常关键的应用中很有前景。
We demonstrate an asymmetric supercapacitor in a potassium acetate-based water-in-salt electrolyte, where 2-D titanium carbide MXene and manganese oxide were used as negative and positive electrode materials, respectively. Use of water-in-salt electrolyte enables the assembled asymmetric device to be operated up to a cell voltage of 2.2 V, which overcomes the limited cell voltage issue in aqueous pseudocapacitors (1.2 - 1.4 V). This cell shows excellent rate capability (similar to 48%) between 5 and 100 mV s(-1) and good stability (similar to 93%) throughout 10,000 charge-discharge cycles (at 1 A g(-1)) and 25 h voltage-hold at 2.2 V, which is competitive when compared with the performance of known asymmetric supercapacitors designed with activated carbon electrodes and fluorinated-imide based water-in-salt electrolytes. Moreover, our device shows slower self-discharge and similar to 32% higher volumetric energy density than activated carbon-based supercapacitors and is promising for applications where volumetric energy density is critical.