Su Yu, Zhang Ning-Ning, Li Jia-Yang, Liu Yifeng, Hu Hai-Yan, Wang Jingqiang, Li Hongwei, Kong Ling-Yi, Jia Xin-Bei, Zhu Yan-Fang, Chen Shuangqiang, Wang Jia-Zhao, Dou Shi-Xue, Chou Shulei, Xiao Yao
Institute for Carbon Neutralization, College of Chemistry and Materials Engineering, Wenzhou University, Wenzhou 325035, China.
Wenzhou Key Laboratory of Sodium-Ion Batteries, Wenzhou University Technology Innovation Institute for Carbon Neutralization, Wenzhou 325035, China.
ACS Appl Mater Interfaces. 2023 Sep 27;15(38):44839-44847. doi: 10.1021/acsami.3c07164. Epub 2023 Sep 11.
Manganese-based layered oxides are prospective cathode materials for sodium-ion batteries (SIBs) due to their low cost and high theoretical capacities. The biphasic intergrowth structure of layered cathode materials is essential for improving the sodium storage performance, which is attributed to the synergistic effect between the two phases. However, the in-depth formation mechanism of biphasic intergrowth materials remains unclear. Herein, the layered/tunnel intergrowth NaMnO (LT-NaMO) as a model material was successfully prepared, and their formation processes and electrochemical performance were systematically investigated. In situ high-temperature X-ray diffraction displays the detailed evolution process and excellent thermal stability of the layered/tunnel intergrowth structure. Furthermore, severe structural strain and large lattice volume changes are significantly mitigated by the interlocking effect between the phase interfaces, which further enhances the structural stability of the cathode materials during the charging/discharging process. Consequently, the LT-NaMO cathode displays fast Na transport kinetics with a remarkable capacity retention of ∼70.5% over 300 cycles at 5C, and its assembled full cell with hard carbon also exhibits high energy density. These findings highlight the superior electrochemical performance of intergrowth materials due to interlocking effects between layered and tunnel structures and also provide unique insights into the construction of intergrowth cathode materials for SIBs.
锰基层状氧化物因其低成本和高理论容量，是钠离子电池（SIBs）颇具前景的阴极材料。层状阴极材料的双相共生结构对于提升储钠性能至关重要，这归因于两相之间的协同效应。然而，双相共生材料的深入形成机制仍不明确。在此，成功制备了层状/隧道共生NaMnO（LT-NaMO）作为模型材料，并系统研究了它们的形成过程和电化学性能。原位高温X射线衍射展示了层状/隧道共生结构的详细演化过程和出色的热稳定性。此外，相界面之间的互锁效应显著减轻了严重的结构应变和大的晶格体积变化，这进一步增强了阴极材料在充放电过程中的结构稳定性。因此，LT-NaMO阴极显示出快速的Na传输动力学，在5C下300次循环中具有约70.5%的显著容量保持率，并且其与硬碳组装的全电池也表现出高能量密度。这些发现突出了共生材料由于层状和隧道结构之间的互锁效应而具有的优异电化学性能，也为SIBs共生阴极材料的构建提供了独特见解。
