Ionic Liquid-Directed Nanoporous TiNb2 O7 Anodes with Superior Performance for Fast-Rechargeable Lithium-Ion Batteries.
Ionic Liquid-Directed Nanoporous TiNb2 O7 Anodes with Superior Performance for Fast-Rechargeable Lithium-Ion Batteries.
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DOI：
10.1002/smll.202001884
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发表时间：
2020-06
期刊：
影响因子：
13.3
通讯作者：
Runming Tao;Guang Yang;Ethan C. Self;Jiyuan Liang;J. Dunlap;Shuang Men;Chi-Linh Do-Thanh;Jixing Liu
中科院分区：
文献类型：
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作者：
Runming Tao;Guang Yang;Ethan C. Self;Jiyuan Liang;J. Dunlap;Shuang Men;Chi-Linh Do-Thanh;Jixing Liu
以离子液体(IL)为纳米孔结构导向模板，采用溶胶-凝胶法合成了纳米孔TiNb2O7(NPTNO)材料。NPTNO在50C充电率下仍有高达210mAHg-1的可逆容量，5C循环1000次半电池容量保持率为74%，1C和2C循环1000次LiNi0.5Mn1.5O4耦合的全电池容量保持率分别为81%和87%。对1000次循环的NPTNO电极的研究表明，IL导向的介孔结构可以缓解重复的Li+插入-提取过程引起的重复机械应力和体积波动，从而提高NPTNO细胞的循环能力。恒电流间歇滴定技术测得的Li+扩散系数表明，基于快速Li+扩散动力学，IL模板策略确实确保了NPTNO电池的快速可充性。得益于纳米孔结构，NPTNO具有畅通的Li+扩散路径，在钛基氧化物材料中实现了优异的倍率性能，在TNO材料中实现了最佳的全电池循环性能。因此，展示了IL的模板潜力，以及优异的电化学性能，使IL导向的NPTNO成为快速充电锂离子电池的一种有前途的阳极候选材料。
Nanoporous TiNb2 O7 (NPTNO) material is synthesized by a sol-gel method with an ionic liquid (IL) as the nanoporous structure directing template. NPTNO exhibits a high reversible capacity of 210 mAh g-1 even at the charging rate of 50 C and an excellent cyclability of half-cell capacity retention of 74% for 1000 cycles at 5 C and LiNi0.5 Mn1.5 O4 -coupled full-cell capacity retentions of 81% and 87% for 1000 cycles at 1 C and 2 C, respectively. The studies of the 1000 cycled NPTNO electrode illustrate that the IL-directed mesoporous structure can enhance the cyclability of NPTNO cells due to the alleviation of repetitive mechanical stress and volume fluctuation induced by the repetitive Li+ insertion-extraction processes. The measured Li+ diffusion coefficients from the galvanostatic intermittent titration technique suggest that the IL-templating strategy indeed ensures the fast rechargeability of NPTNO cells based on the fast Li+ diffusion kinetics. Benefitting from the nanoporous structure, NPTNO with unhindered Li+ diffusion pathways achieves a superior rate capability in the titanium-based oxide materials and the best full-cell cyclability in the TNO materials. Therefore, the templating potential of IL is demonstrated, and the superb electrochemical performance establishes the IL-directed NPTNO as a promising anode candidate for fast-rechargeable LIBs.