Materials Science & Engineering, ‡Aero-propulsion, Mechatronics and Energy Center (AME), §High-Performance Materials Institute (HPMI), and ∥Center for Advanced Power Systems (CAPS), Florida State University , Tallahassee, Florida 32310, United States.
Department of Electrical & Computer Engineering and #Department of Industrial and Manufacturing Engineering, Florida A&M University-Florida State University College of Engineering , Tallahassee, Florida 32310, United States.
ACS Appl Mater Interfaces. 2018 Feb 28;10(8):7155-7161. doi: 10.1021/acsami.7b19246. Epub 2018 Feb 19.
A different strategy of capacity-control cycling under fixed upper and lower capacity/voltage limits is used in an attempt to seek an extended cycle life for Si nanoparticle-multiwalled carbon nanotube (Si-MW) electrodes for Li-ion batteries. For cells using Si-MW 1:1 (w/w) electrodes in the electrolyte of ethylene carbonate-diethyl carbonate-fluoroethylene carbonate (EC-DEC-FEC, 45:45:10 w/w/w) tested at a current of 1 mA, stable 326 charge/discharge cycles at a designated capacity of 506 mA h g are attained. The new cycling protocol allows for the observation of a self-healing phenomenon by studying the specific capacities and charge/discharge end voltages. Prolonged cycling under capacity control (500 mA h g) and the interesting pattern of variations in the discharge/charge end voltage are successfully reproduced under different electrode/electrolyte and current conditions: Si-MW 3:2 in the electrolyte of DEC-FEC (1:1 w/w) at 1 mA (490 cycles), Si-MW 3:2 in DEC-FEC at 0.5 mA (483 cycles), and Si-MW 1:1 in DEC-FEC at 0.5 mA (576 cycles), which can be explained by applying the proposed self-healing mechanism as well.
采用了一种不同的容量控制循环策略，在上、下容量/电压限制固定的情况下，试图为锂离子电池的硅纳米颗粒-多壁碳纳米管（Si-MW）电极寻求更长的循环寿命。在电流为 1 mA 的条件下，使用 Si-MW 1:1（w/w）电极的电解液为碳酸乙烯酯-二乙基碳酸酯-氟代碳酸乙烯酯（EC-DEC-FEC，45:45:10 w/w/w）的电池中，稳定的 326 次充放电循环达到了 506 mA h g 的指定容量。新的循环方案允许通过研究比容量和充放电端电压来观察自修复现象。在不同的电极/电解质和电流条件下，成功地再现了在容量控制（500 mA h g）下的延长循环和放电/充电端电压的有趣变化模式：在 1 mA 下，DEC-FEC（1:1 w/w）中的 Si-MW 3:2（490 次循环），DEC-FEC 中的 Si-MW 3:2（483 次循环），以及 DEC-FEC 中的 Si-MW 1:1（0.5 mA，576 次循环），这可以通过应用所提出的自修复机制来解释。
