A new design with alternately stacked electrode configuration helped to enhance the volumetric performance of Supercapacitors and attained high energy density without sacrificing power performance.
This research, which introduced the alternately stacked electrode structure into compact energy storage system for the first time, was conducted by Prof. HAN Fangming from Institute of Solid State physics,Hefei Institutes of Physical Science, and Prof. WEI Bingqing from University of Delaware, Newark, USA.
In this work, researchers designed an alternately multilayer stacked film electrode structure, using Ti3C2Tx (MXene) films as the electrodes, and gel electrolyte as the separator (Figure 1).
This new structure could shorten the transport distance of ions under high mass loadings, and increase the mass loading of active material at device scale, without increasing the mass loadings of each single electrode.
Thus, the supercapacitor with alternately stacked configuration showed ultrahigh areal capacitance of 10.8 F cm-2, high volumetric energy density of 10.4 mWh cm-3 at 75.0 mW cm-3, and simultaneously maintained high power performance (Figure 3). ¡°It is the highest values in an aqueous gel electrolyte system compared to the literature.¡± Prof. Han says.
With the trend of the miniaturization and portability of electronic devices, it is essential to improve the volumetric energy density of electrochemical energy storage device. High mass loadings can decrease the inactive component ratio at the device level, thereby leading to increased energy density as well as decreased cost.
Unfortunately, the increase of the mass loadings usually comes at the cost of losses in specific capacitance and power density.
This new design could offer a new approach to achieve various advanced high areal and volumetric energy density electrochemical energy storage devices with high mass loadings of active materials.
This work was supported by the National Natural Science Foundation of China (No. 51372247, 91963202).
Link to paper: Alternately stacked thin film electrodes for high-performance compact energy storage
Fig. 1 Assembly of the supercapacitor with an alternately stacked electrode configuration. (Image by PAN Qijuan)
Fig. 2 Comparison of the electrochemical energy storage performances between the supercapacitor with the alternately stacked configuration (9-layer electrodes, including 2-layer 1.7 mg cm-2 films as the outmost electrodes, 7-layer 3.4 mg cm-2 films as the inner), and the supercapacitor with the two-electrode configuration under the same mass loading of active material (the total mass loading of the electrodes is about 27.2 mg cm-2). (Image by PAN Qijuan)
Fig. 3 The device performance evaluation of the supercapacitors with alternately stacked configuration. (Image by PAN Qijuan)