Fernando Niranjala, Veldhuizen Hugo, Nagai Atsushi, van der Zwaag Sybrand, Abdelkader Amor
Department of Engineering, Talbot Campus, Bournemouth University, Fern Barrow, Poole BH12 5BB, UK.
Faculty of Aerospace Engineering, Delft University of Technology, Kluyverweg 1, 2629 Delft, The Netherlands.
Materials (Basel). 2021 Dec 21;15(1):4. doi: 10.3390/ma15010004.
Nanoporous polymers are becoming increasingly interesting materials for electrochemical applications, as their large surface areas with redox-active sites allow efficient adsorption and diffusion of ions. However, their limited electrical conductivity remains a major obstacle in practical applications. The conventional approach that alleviates this problem is the hybridisation of the polymer with carbon-based additives, but this directly prevents the utilisation of the maximum capacity of the polymers. Here, we report a layer-by-layer fabrication technique where we separated the active (porous polymer, top) layer and the conductive (carbon, bottom) layer and used these "layered" electrodes in a supercapacitor (SC). Through this approach, direct contact with the electrolyte and polymer material is greatly enhanced. With extensive electrochemical characterisation techniques, we show that the layered electrodes allowed a significant contribution of fast faradic surface reactions to the overall capacitance. The electrochemical performance of the layered-electrode SC outperformed other reported porous polymer-based devices with a specific gravimetric capacitance of 388 F·g and an outstanding energy density of 65 Wh·kg at a current density of 0.4 A·g. The device also showed outstanding cyclability with 90% of capacitance retention after 5000 cycles at 1.6 A·g, comparable to the reported porous polymer-based SCs. Thus, the introduction of a layered electrode structure would pave the way for more effective utilisation of porous organic polymers in future energy storage/harvesting and sensing devices by exploiting their nanoporous architecture and limiting the negative effects of the carbon/binder matrix.
纳米多孔聚合物正日益成为电化学应用中备受关注的材料，因为其具有氧化还原活性位点的大表面积允许离子进行高效吸附和扩散。然而，其有限的电导率仍然是实际应用中的主要障碍。缓解这一问题的传统方法是将聚合物与碳基添加剂进行混合，但这直接阻碍了聚合物最大容量的利用。在此，我们报告了一种逐层制造技术，我们将活性（多孔聚合物，顶层）层和导电（碳，底层）层分开，并在超级电容器（SC）中使用这些“分层”电极。通过这种方法，与电解质和聚合物材料的直接接触得到了极大增强。通过广泛的电化学表征技术，我们表明分层电极对总电容有快速法拉第表面反应的显著贡献。分层电极超级电容器的电化学性能优于其他已报道的基于多孔聚合物的器件，在电流密度为0.4 A·g时，比重量电容为388 F·g，能量密度高达65 Wh·kg。该器件还表现出出色的循环稳定性，在1.6 A·g下经过5000次循环后电容保持率为90%，与已报道的基于多孔聚合物的超级电容器相当。因此，引入分层电极结构将为未来储能/收集和传感设备中更有效地利用多孔有机聚合物铺平道路，通过利用其纳米多孔结构并限制碳/粘合剂基质的负面影响。
