Department of Chemistry and Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Institute of New Energy, Collaborative Innovation Center of Chemistry for Energy Materials (iChEM) , Fudan University , Shanghai 200433 , China.
ACS Appl Mater Interfaces. 2018 Apr 11;10(14):11689-11698. doi: 10.1021/acsami.8b00478. Epub 2018 Apr 2.
Batteries and electrochemical capacitors play very important roles in the portable electronic devices and electric vehicles and have shown promising potential for large-scale energy storage applications. However, batteries or capacitors alone cannot meet the energy and power density requirements because rechargeable batteries have a poor power property, whereas supercapacitors offer limited capacity. Here, a novel symmetric sodium-ion capacitor (NIC) is developed based on low-cost NaMnO nanorods. The NaMnO with unique nanoarchitectures and iso-oriented feature offers shortened diffusion path lengths for both electronic and Na transport and reduces the stress associated with Na insertion and extraction. Benefiting from these merits, the symmetric device achieves a high power density of 2432.7 W kg, an improved energy density of 27.9 Wh kg, and a capacitance retention of 85.2% over 5000 cycles. Particularly, the symmetric NIC based on NaMnO permits repeatedly reverse-polarity characteristics, thus simplifying energy management system and greatly enhancing the safety under abuse condition. This cost-effective, high-safety, and high-performance symmetric NIC can balance the energy and power density between batteries and capacitors and serve as an electric power source for future low-maintenance large-scale energy storage systems.
电池和电化学电容器在便携式电子设备和电动汽车中起着非常重要的作用，并在大规模储能应用中显示出有前景的潜力。然而，仅靠电池或电容器无法满足能量和功率密度的要求，因为可充电电池的功率特性较差，而超级电容器的容量有限。在这里，我们基于低成本的 NaMnO 纳米棒开发了一种新型对称钠离子电容器 (NIC)。NaMnO 具有独特的纳米结构和各向同性特征，为电子和 Na 传输提供了更短的扩散路径长度，并减少了与 Na 插入和提取相关的应力。得益于这些优点，对称器件实现了 2432.7 W kg 的高功率密度、27.9 Wh kg 的改进能量密度以及 5000 次循环后的 85.2%的电容保持率。特别是，基于 NaMnO 的对称 NIC 允许反复的反向极性特性，从而简化了能量管理系统，并在滥用条件下大大提高了安全性。这种具有成本效益、高安全性和高性能的对称 NIC 可以平衡电池和电容器之间的能量和功率密度，并可用作未来低维护大规模储能系统的电力源。
