Wu Chongrui, Zhang Fuming, Xiao Xiangshang, Chen Junyan, Sun Junqi, Gandla Dayakar, Ein-Eli Yair, Tan Daniel Q
Department of Materials Science and Engineering, Guangdong Technion Israel Institute of Technology, 241 Daxue Road, Jinping District, Shantou 515063, China.
Department of Materials Science and Engineering and Grad Technion Energy Program (GTEP), Technion-Israel Institute of Technology, Haifa 3200003, Israel.
Molecules. 2021 Jul 9;26(14):4188. doi: 10.3390/molecules26144188.
Fabricating electrical double-layer capacitors (EDLCs) with high energy density for various applications has been of great interest in recent years. However, activated carbon (AC) electrodes are restricted to a lower operating voltage because they suffer from instability above a threshold potential window. Thus, they are limited in their energy storage. The deposition of inorganic compounds' atomic layer deposition (ALD) aiming to enhance cycling performance of supercapacitors and battery electrodes can be applied to the AC electrode materials. Here, we report on the investigation of zinc oxide (ZnO) coating strategy in terms of different pulse times of precursors, ALD cycles, and deposition temperatures to ensure high electrical conductivity and capacitance retention without blocking the micropores of the AC electrode. Crystalline ZnO phase with its optimal forming condition is obtained preferably using a longer precursor pulse time. Supercapacitors comprising AC electrodes coated with 20 cycles of ALD ZnO at 70 °C and operated in TEABF/acetonitrile organic electrolyte show a specific capacitance of 23.13 F g at 5 mA cm and enhanced capacitance retention at 3.2 V, which well exceeds the normal working voltage of a commercial EDLC product (2.7 V). This work delivers an additional feasible approach of using ZnO ALD modification of AC materials, enhancing and promoting stable EDLC cells under high working voltages.
近年来，制造具有高能量密度的双电层电容器（EDLC）以用于各种应用引起了人们的极大兴趣。然而，活性炭（AC）电极的工作电压受到限制，因为在高于阈值电位窗口时它们会不稳定。因此，它们的能量存储受到限制。旨在提高超级电容器和电池电极循环性能的无机化合物原子层沉积（ALD）可应用于AC电极材料。在此，我们报告了关于氧化锌（ZnO）涂层策略的研究，该策略涉及前驱体的不同脉冲时间、ALD循环次数和沉积温度，以确保高电导率和电容保持率，同时不堵塞AC电极的微孔。优选使用较长的前驱体脉冲时间获得具有最佳形成条件的结晶ZnO相。在70°C下用20次ALD ZnO循环涂覆AC电极并在TEABF/乙腈有机电解质中运行的超级电容器，在5 mA cm时的比电容为23.13 F g，在3.2 V时电容保持率提高，这远远超过了商用EDLC产品的正常工作电压（2.7 V）。这项工作提供了一种额外的可行方法，即使用ZnO ALD对AC材料进行改性，以增强和促进高工作电压下稳定的EDLC电池。
