The low electronic conductivity and moderate lithium-ion transfer capability of Li2ZnTi3O8 restrict its application to some degree. In this work, in light of the high affinity of TiO2 surface with carboxylic acids, citric acid was adopted as a carbon source to form uniform carbon coating layer on LZTO particles. When the mixture of LZTO and citric acid with a mass ratio of 1:0.2 was roasted at 700 °C for 5 h, the product demonstrated wonderful rate performance (revealing capacities of 232.6, 202.8, 184.8, 165.6 and 106.7 mAh g−1 at 0.1, 0.2, 0.4, 0.8 and 1.6 A g−1, respectively) as well as outstanding long-term cycling stability (maintaining a capacity of 186.9 mAh g−1 for 1000 cycles at 0.5 A g−1). Combining structure and composition characterizations with electrochemical impedance spectra analysis, the amorphous carbon derived from citric acid was uniformly coated on the LZTO particles by virtue of the intense interaction between LZTO and carboxyl groups. Better particle dispersion and enhanced pseudocapacitive contribution were obtained resulted from the carbon coating, remarkably ameliorating the electronic and ionic conductivities of LZTO and alleviating polarization, thus beneficial to optimizing the electrochemical behavior of LZTO.

中文翻译：

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通过形成由柠檬酸衍生的均匀薄碳涂层优化 Li2ZnTi3O8 的循环寿命和高倍率性能

Li2ZnTi3O8 的低电子电导率和适度的锂离子转移能力在一定程度上限制了其应用。在这项工作中，鉴于 TiO2 表面与羧酸的高亲和力，采用柠檬酸作为碳源，在 LZTO 颗粒上形成均匀的碳涂层。当质量比为 1:0.2 的 LZTO 和柠檬酸的混合物在 700 °C 下焙烧 5 h 时，该产品表现出优异的倍率性能（在0.1、0.2、0.4、0.8 和 1.6 A g-1）以及出色的长期循环稳定性（在 0.5 A g-1 下在 1000 次循环中保持 186.9 mAh g-1 的容量）。将结构和成分表征与电化学阻抗谱分析相结合，由于LZTO与羧基之间的强烈相互作用，源自柠檬酸的无定形碳均匀地包覆在LZTO颗粒上。碳涂层获得了更好的颗粒分散和增强的赝电容贡献，显着改善了LZTO的电子和离子电导率并减轻了极化，从而有利于优化LZTO的电化学行为。