Nankai’s Ph.D. student published the Result of his Research on Aqueous Zn-Ion Battery in JACS

2016.12.07

    Zhang Ning, a Ph.D. student of Nankai University’s College of Chemistry, published the result of his research on Aqueous Zn-Ion Battery in JACS, an authoritative journal of Material Science and Chemistry. Zhang Ning is the first author, and Prof. Cheng Fangyi, his tutor, is the coauthor. The researcher has already applied for a patent. In the paper, the team reports the application of nonstoichiometric ZnMn2O4/carbon composite as a new Zn-insertion cathode material in aqueous Zn(CF3SO3)2 electrolyte.

    Zhang Ning explained: “While lithium-ion batteries (LIBs) have gained huge success to power portable electronics and been considered for applications in electric vehicles and large-scale energy storage, there are growing concerns over their cost, safety, environmental impact, and resource limitation. In the research on alternative batteries, systems made of other lightweight electropositive elements (e.g., Na, Mg, Al, and Ca) have attracted extensive interest because of the abundance of the materials and their cost. Meanwhile, the use of aqueous electrolyte to replace organic electrolyte offers advantages: it is safer, greener, the manufacturing conditions are less rigorous, and it has higher ionic conductivity. In this regard, aqueous Zn-ion battery (ZIB) technologies hold particular promise as Zn features low flammability and high water compatibility, and allows multivalent charge transport carriers. Rechargeable aqueous Zn-ion batteries are attractive cheap, safe and green energy storage technologies but are bottlenecked by limitation in high-capacity cathode and compatible electrolyte to achieve satisfactory cyclability. The remarkable electrode performance results from the facile charge transfer and Zn insertion in the structurally robust spinel featuring small particle size and abundant cation vacancies, as evidenced by combined electrochemical measurements, XRD, Raman, synchrotron X-ray absorption spectroscopy, FTIR, and NMR analysis. The results would enlighten and promote the use of cation-defective spinel compounds and trifluoromethanesulfonic electrolyte to develop high-performance rechargeable zinc batteries.” Zhang Ning stressed that these advanced techniques can explain this scientific phenomenon more clearly.

     The application of Zn-Ion battery is not only high-efficient and stable but can also lower the costs. According to the research, the price of Zn in the market is about 2 dollars/kg, while lithium costs around 300 dollars/kg. Zn could reach the annual production of 5 million tons, while lithium’s production is around 40 thousand tons/year. The crustal abundance of these two metals is respectively 80 ppm and 17 ppm. Zn is more accessible and costs less, so it is more suitable for a large-scale production. 

     However, the Aqueous Zn-Ion Battery still has problems. Zhang Ning honestly said that the energy density of the battery’s cathode material is relatively low (about half of Lithium battery’s energy density), so it is more suitable for large-scale energy-storing systems rather than portable electric devices such as cell phones. “Our future task is to develop a high-voltage and high-volume cathode material to improve the energy density of the battery.