Researchers at Changzhou University in China are developing a “binary-ion” battery system—a battery that uses cooperative behavior between Zn2+ and Li+ ions to conduct charge in a Zn/LiFePO4 battery.
|Cycling behavior of Zn|CH3COOLi+Zn(CH3COO)2|LiFePO4 battery at 1 C rate in the window range 0.5–1.7 V at room temperature. Source: Zhang (2013). Click to enlarge.|
In a study reported in the RSC journal Chemical Communications, the team used an LiFePO4 cathode and a piece of polished metal zinc as the counter and the reference. The cathode and anode were immersed into a CH3COOLi (15 wt%) and Zn(CH3COO)2 (15 wt%) aqueous mixture to obtain the Zn|CH3COOLi+Zn(CH3COO)2|LiFePO4 battery.
When Li+ dissolves into the electrolyte, Zn2+ would deposit, and vice versa. In light of this cooperation behavior, the battery can be viewed as a super hybrid system, which combines the strong points of Zn-air battery, lithium-ion battery and redox-flow cell together.—Zhang et al. (2013)
In a prior paper published in the Journal of the Electrochemical Society, Zhang et al. had explored a Zn|CH3COOLi+Zn(CH3COO)2|LiMn2O4 binary ion battery system, calling it a “typical Newton’s cradle system”.
The charge-discharge curves and cycling calendar life as well as current rate performance indicate that the work mechanism based on Newton’s cradle model operates well, the sustainable current rate larger than 20C suggests that this system can offer a considerable high power.—Zhang et al. (2012)
Hanping Zhang, Xin Wu, Tao Yang, Shanshan Liang and Xiaojian Yang (2013) Cooperation behavior between heterogeneous cations in hybrid batteries. Chem Comm. doi: 10.1039/C3CC45895D
Hanping Zhang, Qing Du, Chenggang Li and Xiaohui Sun (2012) Binary Ion Batteries Operating on the Model of Newton’s Cradle. J. Electrochem. Soc. volume 159, issue 12, A2001-A2004 doi: 10.1149/2.082212jes