Zhu Zhuo, Shi Xiaomeng, Zhu Dongdong, Wang Liubin, Lei Kaixiang, Li Fujun
Key Laboratory of Advanced Energy Materials Chemistry (Ministry of Education), College of Chemistry, Nankai University, Tianjin 300071, China.
Research (Wash D C). 2019 Jan 16;2019:6180615. doi: 10.34133/2019/6180615. eCollection 2019.
Na-O and K-O batteries have attracted extensive attention in recent years. However, the parasitic reactions involving the discharge product of NaO or K anode with electrolytes and the severe Na or K dendrites plague their rechargeability and cycle stability. Herein, we report a hybrid Na//K-containing electrolyte//O battery consisting of a Na anode, 1.0 M of potassium triflate in diglyme, and a porous carbon cathode. Upon discharging, KO is preferentially produced via oxygen reduction in the cathode with Na stripped from the Na anode, and reversely, the KO is electrochemically decomposed with Na plated back onto the anode. The new reaction pathway can circumvent the parasitic reactions involving instable NaO and active K anode, and alternatively, the good stability and conductivity of KO and stable Na stripping/plating in the presence of K enable the hybrid battery to exhibit an average discharge/charge voltage gap of 0.15 V, high Coulombic efficiency of >96%, and superior cycling stability of 120 cycles. This will pave a new pathway to promote metal-air batteries.
近年来，钠氧电池和钾氧电池引起了广泛关注。然而，涉及钠阳极或钾阳极放电产物与电解质的寄生反应以及严重的钠枝晶或钾枝晶问题困扰着它们的可充电性和循环稳定性。在此，我们报道了一种由钠阳极、二甘醇二甲醚中1.0 M的三氟甲磺酸钾和多孔碳阴极组成的混合钠//含钾电解质//氧电池。放电时，通过阴极的氧还原优先生成KO，同时钠从钠阳极剥离，相反地，KO被电化学分解，钠重新镀回到阳极上。这种新的反应途径可以避免涉及不稳定的NaO和活性钾阳极的寄生反应，此外，KO良好的稳定性和导电性以及在钾存在下稳定的钠剥离/镀覆使混合电池能够表现出0.15 V的平均放电/充电电压差、>96%的高库仑效率以及120次循环的优异循环稳定性。这将为促进金属空气电池的发展开辟一条新途径。
