Zheng Nan, Zhang Chang, Lv Yinjie, Cheng Lvyang, Yao Lei, Liu Wei
Hanshan Normal University, Chaozhou 521041, China.
School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China.
ACS Appl Mater Interfaces. 2022 Mar 9;14(9):11330-11338. doi: 10.1021/acsami.1c22665. Epub 2022 Feb 25.
Due to the lower working voltage and higher capacity, the Li-rich lithium lanthanum titanate perovskite (LLTO) anode is becoming a potential candidate for the commercial LiTiO (LTO) Li-ion battery anode [Zhang, L. Lithium Lanthanum Titanate Perovskite as an Anode for Lithium Ion Batteries. 2020, 11, 3490]. However, a high temperature of 1250 °C is required to fabricate pure LLTO particles by the conventional solid-phase calcination method, limiting their further practical applications. Here, an carbon nanospace confined method is developed to synthesize the pure LLTO with sub-nanometer grain size at an extremely low temperature of 800 °C. The LLTO precursor is confined in the formed carbon nanowire matrix during heating, resulting in a shorter solid-phase diffusion distance and subsequently lower energy required for the formation of the pure LLTO phase. The low-temperature-synthesized pure LLTO/carbon composite nanowires (P-LLTO/C NWs) exhibit improved lithium storage performances than the traditionally prepared LLTO due to the fast electronic conduction of carbon and the stable carbon surface. In addition, the working potentials of P-LLTO/C||LiFePO and P-LLTO/C||LiCoO full cells are all 0.7 V higher than that of the corresponding commercial full cells with LTO as an anode, meaning much higher power energy densities (307.6 W kg at 2C and 342.4 W kg at 1C 198.4 W kg and 275.2 W kg for LTO||LiFePO and LTO||LiCoO full cells based on electrode materials, respectively). This low-temperature synthesis method can extend to other solid-state ionic materials and electrode materials for electrochemical devices.
由于工作电压较低且容量较高，富锂钛酸镧钙钛矿（LLTO）负极正成为商用钛酸锂（LTO）锂离子电池负极的潜在候选材料[张，L. 钛酸镧钙钛矿作为锂离子电池负极。2020，11，3490]。然而，通过传统的固相煅烧法制备纯LLTO颗粒需要1250℃的高温，这限制了它们的进一步实际应用。在此，开发了一种碳纳米空间限制方法，以在800℃的极低温度下合成具有亚纳米晶粒尺寸的纯LLTO。加热过程中，LLTO前驱体被限制在形成的碳纳米线基质中，导致固相扩散距离缩短，随后形成纯LLTO相所需的能量降低。低温合成的纯LLTO/碳复合纳米线（P-LLTO/C NWs）由于碳的快速电子传导和稳定的碳表面，表现出比传统制备的LLTO更好的锂存储性能。此外，P-LLTO/C||LiFePO和P-LLTO/C||LiCoO全电池的工作电位均比以LTO为负极的相应商用全电池高0.7 V，这意味着功率能量密度更高（基于电极材料，在2C时为307.6 W kg，在1C时为342.4 W kg，LTO||LiFePO和LTO||LiCoO全电池分别为198.4 W kg和275.2 W kg）。这种低温合成方法可以扩展到其他固态离子材料和用于电化学装置的电极材料。
