Du Hoang-Long, Jeong Min-Gi, Lee Yoon-Sung, Choi Wonchang, Lee Joong Kee, Oh In-Hwan, Jung Hun-Gi
†Center for Energy Convergence, Green City Technology Institute, Korea Institute of Science and Technology, Hwarangno 14 gil 5, Seongbuk-gu, Seoul 136-791, Republic of Korea.
§Department of Energy and Environmental Engineering, Korea University of Science and Technology, 176 Gajungro, Yuseong-gu, Daejeon 305-350, Republic of Korea.
ACS Appl Mater Interfaces. 2015 May 20;7(19):10250-7. doi: 10.1021/acsami.5b00776. Epub 2015 May 8.
Nitrogen-doped carbon is coated on lithium titanate (Li4Ti5O12, LTO) via a simple chemical refluxing process, using ethylenediamine (EDA) as the carbon and nitrogen source. The process incorporates a carbon coating doped with a relatively high amount of nitrogen to form a conducting network on the LTO matrix. The introduction of N dopants in the carbon matrix leads to a higher density of C vacancies, resulting in improved lithium-ion diffusion. The uniform coating of nitrogen-doped carbon on Li4Ti5O12 (CN-LTO) enhances the electronic conductivity of a CN-LTO electrode and the corresponding electrochemical properties of the cell employing the electrode. The results of our study demonstrate that the CN-LTO anode exhibits higher rate capability and cycling performance over 100 cycles. From the electrochemical tests performed, the specific capacity of CN-LTO electrode at higher rates of 20 and 50 C are found to be 140.7 and 82.3 mAh g(-1), respectively. In addition, the CN-Li4Ti5O12 anode attained higher capacity retention of 100% at 1 C rate after 100 cycles and 92.9% at 10 C rate after 300 cycles.
通过简单的化学回流法，以乙二胺（EDA）作为碳源和氮源，在钛酸锂（Li4Ti5O12，LTO）表面包覆氮掺杂碳。该过程形成了一种掺杂有相对大量氮的碳涂层，在LTO基体上形成导电网络。在碳基体中引入N掺杂剂会导致更高密度的C空位，从而改善锂离子扩散。在Li4Ti5O12（CN-LTO）上均匀包覆氮掺杂碳提高了CN-LTO电极的电子导电性以及采用该电极的电池相应的电化学性能。我们的研究结果表明，CN-LTO负极在100次循环中表现出更高的倍率性能和循环性能。从所进行的电化学测试中发现，CN-LTO电极在20 C和50 C的较高倍率下的比容量分别为140.7和82.3 mAh g(-1)。此外，CN-Li4Ti5O12负极在1 C倍率下经过100次循环后容量保持率达到100%，在10 C倍率下经过300次循环后容量保持率为92.9%。
