Sheng Chuanchao, Yu Fengjiao, Wu Yuping, Peng Zhangquan, Chen Yuhui
State Key Laboratory of Materials-oriented Chemical Engineering, College of Chemical Engineering and School of Energy Science and Engineering, Nanjing Tech University, Nanjing, Jiangsu, 211816, China.
State Key Laboratory of Electroanalytical Chemistry Changchun, Institute of Applied Chemistry, Chinese Academy of Science, Changchun, Jilin, 130022, China.
Angew Chem Int Ed Engl. 2018 Jul 26;57(31):9906-9910. doi: 10.1002/anie.201804726. Epub 2018 Jul 4.
The sodium oxygen battery is a promising metal-air battery; however, the discharge process is not well understood and the major discharge product is still under debate. The discharge products determined the theoretical specific energy and electrochemical performance of the battery. Now it is demonstrated that NaO spontaneously disproportionates to Na O , no matter whether it is dissolved in solution or stays on the surface. The behaviors of NaO in solution and on the surface are different. Solvents play a crucial effect on the disproportionation of dissolved NaO species, which is fast in low donor number (DN) solvents such as acetonitrile but sluggish in high DN solvents such as DMSO. In situ XRD results exhibited the different product growing processes in various solvents. Surface NaO would slowly disproportionate to Na O anyway, but this process is relatively slow compared to the time span of discharge process and it does not affect the major product on discharge.
钠氧电池是一种很有前景的金属空气电池；然而，其放电过程尚未得到充分理解，主要放电产物仍存在争议。放电产物决定了电池的理论比能量和电化学性能。现在已经证明，无论NaO是溶解在溶液中还是留在表面，它都会自发歧化成Na₂O₂。NaO在溶液中和表面的行为有所不同。溶剂对溶解的NaO物种的歧化起着关键作用，在低给体数（DN）的溶剂如乙腈中歧化很快，但在高DN的溶剂如二甲基亚砜中则很缓慢。原位XRD结果显示了在各种溶剂中不同的产物生长过程。表面的NaO无论如何都会缓慢歧化成Na₂O₂，但与放电过程的时间跨度相比，这个过程相对较慢，并且它不会影响放电时的主要产物。
