Shi Wenjing, Li Hengxiang, Wang Zihan, Liu Lingyang, Feng Yixin, Qiao Rui, Zhang Ding, Li Haibo, Wang Zhaoyang, Zhang Pengfang
Shandong Provincial Key Laboratory of Chemical Energy Storage and Novel Cell Technology, School of Chemistry and Chemical Engineering, Liaocheng University, Liaocheng 252059, China.
School of Chemical Engineering and Pharmacy, Wuhan Institute of Technology, Wuhan 430205, China.
Molecules. 2025 May 15;30(10):2175. doi: 10.3390/molecules30102175.
Tunnel-type NaMnO is extensively regarded as an appealing cathode for sodium-ion batteries due to its cost-effectiveness and excellent cycling performance. However, low theoretical capacity, resulting from insufficient Na storage sites, hinders its practical application. Herein, the strategy of constructing a tunnel-phase-dominated layered/tunnel biphasic compound was proposed via trace W-substitution and the co-precipitation method. Experimental analysis reveals that W-introduction can effectively redistribute electronic configuration, induce tunnel-to-layered structure evolution, accelerate Na (de)intercalation kinetics, and enhance structural stability. The optimized layered/tunnel NaMnWO cathode integrates the superiorities of the layered and tunnel structures, delivering a high capacity of 153.1 mAh g at 0.1 C and outstanding cycle life, with 71% capacity retention over 600 cycles at 5 C. Significantly, the full cell assembled with the NaMnWO cathode and a commercial hard carbon anode exhibits a competitive energy density of 183.2 Wh kg, along with a remarkable capacity retention of 75.5% over 200 cycles at 1 C. This work not only highlights the superior sodium storage performance of biphasic composites owing to the synergistic effects between layered and tunnel structures, but also unveils new possibilities for constructing high-performance hybrid cathodes that predominantly consist of the tunnel phase using a suitable design strategy.
隧道型NaMnO由于其成本效益和出色的循环性能，被广泛认为是钠离子电池有吸引力的正极材料。然而，由于钠存储位点不足导致的理论容量较低，阻碍了其实际应用。在此，通过微量W取代和共沉淀法提出了构建以隧道相为主的层状/隧道双相化合物的策略。实验分析表明，引入W可以有效地重新分布电子构型，诱导隧道到层状结构的演变，加速Na（脱）嵌动力学，并增强结构稳定性。优化后的层状/隧道NaMnWO正极整合了层状和隧道结构的优势，在0.1 C电流下具有153.1 mAh g的高容量和出色的循环寿命，在5 C电流下600次循环后容量保持率为71%。值得注意的是，由NaMnWO正极和商用硬碳负极组装的全电池具有183.2 Wh kg的竞争能量密度，在1 C电流下200次循环后容量保持率高达75.5%。这项工作不仅突出了由于层状和隧道结构之间的协同效应，双相复合材料具有优异的储钠性能，还揭示了使用合适的设计策略构建以隧道相为主的高性能混合正极的新可能性。
