Study on characteristics of positive and negative electrodes with tin-sulfide lithium ion capacitor

• Main Authors: Yu-Shun Luo, 羅宇舜
• Other Authors: Dah-Shyang Tsai
• Format: Others
• Language: zh-TW
• Published: 2019
• Online Access: http://ndltd.ncl.edu.tw/handle/7htp95

碩士 === 國立臺灣科技大學 === 化學工程系 === 107 === The storage capability of lithium ion hybrid capacitor can be upgraded through adjusting the mismatched rate qualities between positive and negative electrodes, since the positive electrode of electrostatic double layer (EDL) stores and releases electricity in a lesser quantity, yet much faster than the negative battery electrode. To increase the EDL capacity, a nitrogen-doped carbon (KP-N-900) of hollow-polygon structure is prepared with para-phenylphenol, achieving a surface area above 3000 m2g-1. MWCNT must be oxidized and coated with molten tin and sulfur on Multi-wall carbon nanotubes, Sn+SnS@CNT, evidenced by a capacity approximating 103 mAh g-1 at 10.0 A g-1. On the other hand, The capacitance of KP-N-900 displays a diffusive component 44.9 F g-1 exceeding its capacitive counterpart at 10 mV s-1. And its total capacitance increases to 107.1 F g-1 at 1 mV s-1 with a diffusive component 69.6 F g-1. Hence, the full cell, with a 4:1 mass ratio of KP-N-900 to Sn+SnS@CNT exhibits an effectual trade-off between its energy and power, quite different from the one-sided dependence on the carbon electrode of most hybrid capacitors. Specifically, this 4:1 full cell stores 143.3 Wh kg-1 at a power level 0.15 kW kg-1, and 23.4Wh kg-1 at power 16.9 kW kg-1. In terms of stability, after maintaining 3.8V for 100 hours, the capacity retention rate is 80%.