College of Aerospace Engineering, Chongqing University, Chongqing, 400044, P.R. China.
Materials Science Group, Department of Mechanical Engineering, National University of Singapore, Singapore, 117575, Singapore.
Sci Rep. 2017 Mar 23;7(1):373. doi: 10.1038/s41598-017-00346-x.
Rechargeable lithium batteries have been well-known and indispensable for portable electronic devices, and have the potential to be used in electric vehicles and smart grids. However, the growing concerns about the availability of lithium resources for large-scale applications have revived interest in sodium ion batteries. Of many obstacles to commercialization of Na-ion batteries, achieving simultaneously a large reversible capacity and good cycling capability of electrode materials remains a major challenge. Here, we report a new cathode material, Na-rich layered oxide NaTiCrO, that delivers high reversible capacity of 336 mAh g at current density of 18.9 mA g along with promising cycling capability of 74% capacity retention over 1000 cycles at current of 378 mA g. The high capacity is associated to the redox reaction of oxygen, which is confirmed here by a combined experimental and theoretical study. The present work therefore shows that materials beyond mainstream layered oxides and polyanion compounds should be considered as candidate high-performance cathodes for Na-ion batteries.
可充电锂电池在便携式电子设备中已经广为人知且不可或缺，并且有可能用于电动汽车和智能电网。然而，对于大规模应用中锂资源的供应日益关注，重新激发了对钠离子电池的兴趣。在钠离子电池商业化的诸多障碍中，同时实现电极材料的高可逆容量和良好的循环性能仍然是一个主要挑战。在这里，我们报告了一种新的正极材料，富钠层状氧化物 NaTiCrO，它在 18.9 mA g 的电流密度下提供了 336 mAh g 的高可逆容量，并且在 378 mA g 的电流下经过 1000 次循环后具有 74%的容量保持率，具有良好的循环性能。高容量与氧的氧化还原反应有关，这一点在实验和理论研究中得到了证实。因此，本工作表明，应该考虑超越主流层状氧化物和多阴离子化合物的材料作为钠离子电池的候选高性能正极材料。
