Gandla Dayakar, Song Guanghui, Wu Chongrui, Ein-Eli Yair, Tan Daniel Q
Guangdong Technion Israel Institute of Technology, 241 Daxue Road, Jinping District, Shantou, Guangdong, 515063, China.
Technion Israel Institute of Technology, Haifa, 3200003, Israel.
ChemistryOpen. 2021 Apr;10(4):402-407. doi: 10.1002/open.202000352. Epub 2021 Feb 15.
Designing high voltage (>3 V) and stable electrochemical supercapacitors with low self-discharge is desirable for the applications in modern electronic devices. This work demonstrates a 4 V symmetric supercapacitor with stabilized cycling performance through atomic layer deposition (ALD) of alumina (Al O ) on the surface of activated carbon (AC). The 20-cycle ALD Al O coated AC delivers 84 % capacitance retention after 1000 charge/discharge cycles under 4 V, contrary to the bare AC cells having only 48 % retention. The extended cycling life is associated with the thickened Stern layer and suppressed oxygen functional group. The self-discharge data also show that the Al O coating enables AC cells to maintain 53 % of charge retention after 12 h, which is more than twice higher than that of bare AC cells under the same test protocol of 4 V charging. The curve fitting analysis reveals that ALD coating induced slow self-discharge dominated by ion diffusion mechanism, thus enhancing the AC surface energy.
设计具有低自放电特性的高压（>3V）且稳定的电化学超级电容器对于现代电子设备的应用来说是很有必要的。这项工作展示了一种4V对称超级电容器，通过在活性炭（AC）表面进行氧化铝（Al₂O₃）的原子层沉积（ALD）实现了稳定的循环性能。经过20次ALD Al₂O₃涂层处理的AC在4V下进行1000次充放电循环后，电容保持率为84%，而未处理的AC电池仅为48%。循环寿命的延长与加厚的斯特恩层和被抑制的氧官能团有关。自放电数据还表明，Al₂O₃涂层使AC电池在4V充电的相同测试协议下，12小时后能够保持53%的电荷保留率，这比未处理的AC电池高出两倍多。曲线拟合分析表明，ALD涂层导致由离子扩散机制主导的缓慢自放电，从而提高了AC的表面能。
