Yiping Zou1, Tingting Liu1, Qijun Du1, Yingying Li1, Haibo Yi1, Xing Zhou1, Zhuxin Li1, Lujie Gao1, Lan Zhang1, Xiao Liang2,3. 1. State Key Laboratory of Chem/Bio-Sensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha, 410082, P.R. China. 2. State Key Laboratory of Chem/Bio-Sensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha, 410082, P.R. China. xliang@hnu.edu.cn. 3. Advanced Catalytic Engineering Research Center of the Ministry of Education, Hunan University, Changsha, 410082, P.R. China. xliang@hnu.edu.cn.
Abstract
Electrochemically reversible redox couples that embrace more electron transfer at a higher potential are the eternal target for energy storage batteries. Here, we report a four-electron aqueous zinc-iodine battery by activating the highly reversible I2/I+ couple (1.83 V vs. Zn/Zn2+) in addition to the typical I-/I2 couple (1.29 V). This is achieved by intensive solvation of the aqueous electrolyte to yield ICl inter-halogens and to suspend its hydrolysis. Experimental characterization and modelling reveal that limited water activity and sufficient free chloride ions in the electrolyte are crucial for the four-electron process. The merits of the electrolyte also afford to stabilize Zn anode, leading to a reliable Zn-I2 aqueous battery of 6000 cycles. Owing to high operational voltage and capacity, energy density up to 750 Wh kg-1 based on iodine mass was achieved (15-20 wt% iodine in electrode). It pushes the Zn-I2 battery to a superior level among these available aqueous batteries.
Electrochemically reversible redox couples that embrace more electron transfer at a higher potential are the eternal target for energy storage batteries. Here, we report a four-electron aqueous n class="Chemical">zinc-iodine battery by activating the highly reversible I2/I+ couple (1.83 V vs. Zn/Zn2+) in addition to the typical I-/I2 couple (1.29 V). This is achieved by intensive solvation of the aqueous electrolyte to yield ICl inter-halogens and to suspend its hydrolysis. Experimental characterization and modelling reveal that limited water activity and sufficient free chloride ions in the electrolyte are crucial for the four-electron process. The merits of the electrolyte also afford to stabilize Zn anode, leading to a reliable Zn-I2 aqueous battery of 6000 cycles. Owing to high operational voltage and capacity, energy density up to 750 Wh kg-1 based on iodine mass was achieved (15-20 wt% iodine in electrode). It pushes the Zn-I2 battery to a superior level among these available aqueous batteries.
Authors: D Aurbach; Z Lu; A Schechter; Y Gofer; H Gizbar; R Turgeman; Y Cohen; M Moshkovich; E Levi Journal: Nature Date: 2000-10-12 Impact factor: 49.962