Hierarchical Li4Ti5O12 particles co-modified with C&N towards enhanced performance in lithium-ion battery applications
Hierarchical Li4Ti5O12 particles co-modified with C&N towards enhanced performance in lithium-ion battery applications
复制标题
DOI：
10.1016/j.electacta.2013.11.038
复制
发表时间：
2014-01
影响因子：
6.6
通讯作者：
H. Ming;Jun Ming;Xiaowei Li;Qun Zhou;Haohe Wang;Lingling Jin;Yue Fu;J. Adkins;Junwei Zheng
中科院分区：
文献类型：
--
作者：
H. Ming;Jun Ming;Xiaowei Li;Qun Zhou;Haohe Wang;Lingling Jin;Yue Fu;J. Adkins;Junwei Zheng
通过简单合成，制备了在锂离子电池中具有优异性能的碳和氮（C&N）共改性分级Li4Ti5O12（LTO）颗粒，其中C和N的适当改性成功地降低了极化并提高了LTO的电导率，同时由于C&N的还原能力而产生了Ti3+位点。加上小于10 nm的初级纳米晶和相对较高的比表面积（16.9 m2g−1），所制备的样品表现出优异的电化学性能，例如在0.1 C的电流倍率下约174.7 mAh g−1的高容量以及在1和10 C的电流倍率下100次循环后超过171和150 mAh g−1的可逆容量（1 C = 175 mAh g−1）。更重要的是，首次研究了LTO中C&N改性的最佳量。研究发现，C&N的过度改性会引入大量非晶态TiONx，并产生不需要的Ti2+，从而引起LTO的结构转变，直接导致倍率容量低。
Carbon and nitrogen, (C&N), co-modified hierarchical Li4Ti5O12(LTO) particles with excellent perfomance in lithium-ion batteries were preparedviaa facile synthesis with the proper modifying of C and N successfully reducing the polarization and enhancing the conductivity of LTO while also giving rise to Ti3+sites due to the reduction ability of C&N. Together, with primary nanocrystals less than 10 nm and a relatively high specific surface area (16.9 m2g−1), as-prepared samples exhibit excellent electrochemical performance, such as a high capacity around 174.7 mAh g−1at the current rate of 0.1 C and reversible capacity over 171 and 150 mAh g−1after 100 cycles at the current rate of 1 and 10 C (1 C = 175 mAh g−1). More importantly, the optimal amount of C&N modifying in LTO was investigated for the first time. It was found that excessive modifying of C&N can introduce a lot of amorphous TiONxand also create undesirable Ti2+to induce a structural transformation of LTO, directly leading to a low rate capacity.