Zhang Yu, Wang Mengyao, Fan Hao, Huang Chenyang, Liu Mingfei, Liang Xiaofa, Hu Ping, Wang Xuanpeng, Wang Qin, Lv Fei, Zhou Liang
State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, Wuhan 430070, China.
Key Laboratory of Intelligent Sensing System and Security of the Ministry of Education, Hubei Key Laboratory of Micro-Nanoelectronic Materials and Devices, School of Microelectronics, Hubei University, Wuhan 430062, China.
Materials (Basel). 2025 May 22;18(11):2419. doi: 10.3390/ma18112419.
Natrium superionic conductor (NASICON) compounds have emerged as a rising star in the field of sodium-ion batteries (SIBs) owing to their stable framework structure and high Na ionic conductivity. The NASICON-structured NaVTi(PO) manifests significant potential as Na storage material, characterized by decent rate capability and cyclability. However, the low redox potential of Ti/Ti and undesirable energy density limit its practical applications. We developed a NASICON-structured NaCoVTi(PO) (NCTVP) cathode material by doping an appropriate amount of cobalt into NaVTi(PO). Cobalt doping introduces a Co/Co redox couple at ~4.1 V and activates the V/V redox at ~3.9 V, resulting in significantly increased medium discharge voltage and capacity. NCTVP demonstrates a high capacity of over 160 mAh g at 20 mA g. With a medium discharge voltage of ~2.7 V, the energy density of NCTVP reaches 432.0 Wh kg. NCTVP also demonstrates desirable cycling stability (87.4% retention for 100 cycles at 50 mA g). In situ X-ray diffraction discloses a solid solution reaction mechanism for NCTVP, while the galvanostatic intermittent titration technique demonstrates fast Na diffusion kinetics. NCTVP also demonstrates high capacity and good cyclability in full cells. This contribution demonstrates an effective approach for the construction of NASICON materials for SIBs.
钠超离子导体（NASICON）化合物因其稳定的骨架结构和高的钠离子电导率，已成为钠离子电池（SIBs）领域的一颗新星。NASICON结构的NaVTi(PO)作为一种钠存储材料具有显著的潜力，其特点是具有良好的倍率性能和循环稳定性。然而，Ti/Ti的低氧化还原电位和不理想的能量密度限制了其实际应用。我们通过向NaVTi(PO)中掺杂适量的钴，开发了一种NASICON结构的NaCoVTi(PO)（NCTVP）正极材料。钴掺杂引入了4.1 V的Co/Co氧化还原对，并激活了3.9 V的V/V氧化还原，导致中值放电电压和容量显著增加。NCTVP在20 mA g时表现出超过160 mAh g的高容量。中值放电电压约为2.7 V，NCTVP的能量密度达到432.0 Wh kg。NCTVP还表现出理想的循环稳定性（在50 mA g下100次循环保留率为87.4%）。原位X射线衍射揭示了NCTVP的固溶体反应机理，而恒电流间歇滴定技术表明其具有快速的钠扩散动力学。NCTVP在全电池中也表现出高容量和良好的循环稳定性。本研究为构建用于SIBs的NASICON材料提供了一种有效方法。
