Hierarchical Li4Ti5O12/C composite for lithium-ion batteries with enhanced rate performance
Hierarchical Li4Ti5O12/C composite for lithium-ion batteries with enhanced rate performance
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DOI：
10.1016/j.electacta.2017.03.032
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发表时间：
2017-05
影响因子：
6.6
通讯作者：
N. Cao;Z. Song;Qiu Liang;Xuejiao Gao;X. Qin
中科院分区：
文献类型：
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作者：
N. Cao;Z. Song;Qiu Liang;Xuejiao Gao;X. Qin
考虑到Li4Ti5O12(LTO)的迷人优点和天然缺陷，我们利用低成本的葡萄糖作为碳源，通过合理的水热路线构建了多级LTO/C复合材料。获得的复合材料由一些颗粒状二次颗粒（10-15 nm）组成，粘贴在相对大块的 LTO 片材（50-100 nm）上。由于碳的引入，该复合材料具有更小的粒径、更低的极化和优异的导电性。此外，所制备的样品具有良好的循环稳定性和出色的倍率性能。它在 1C 时的放电容量为 174.1 mAh g−1，即使在 50C 时仍保留 131.7 mAh g−1，这明显优于原始 LTO。此外，在1C下循环500次后，放电容量保持在93.4%，在50C下循环1000次后，放电容量保持在80.5%。即使在5C下进行3000次超长循环后，该值仍保留74.2%，远高于纯LTO（38.4%）。还探讨了LTO中碳改性的理想比例。 LTO/C-3.74 wt% 复合材料被证明具有最佳的电化学性能。
Considering the charming merits and natural defects of Li4Ti5O12(LTO), we build a hierarchical LTO/C composite through a rational hydrothermal route by utilizing the low-cost glucose as carbon source. The obtained composite consists of some grain-like secondary particles (10–15 nm) pasted on the relatively bulk LTO sheets (50–100 nm). Due to the introduction of carbon, the composite has the smaller particle size, lower polarization and superior electrical conductivity. Besides, the as-prepared sample exhibits good cycling stability and outstanding rate performance. It delivers the discharge capacity of 174.1 mAh g−1at 1C and left 131.7 mAh g−1even at 50C, which is apparently superior than pristine LTO. Furthermore, the discharge capacity maintains 93.4% after 500 cycles at 1C and 80.5% after 1000 cycles at 50C. Even after 3000 ultralong cycles at 5C, the value still retains 74.2% which is much higher than that of pure LTO (38.4%). The ideal proportion of carbon modified in LTO is also explored. The LTO/C-3.74 wt% composite is demonstrated to possess optimal electrochemical performance.