Zinc-air batteries are considered as potential energy conversion systems. One of the main issues of zinc-air batteries is the low actual power density. However, the three-phase reaction interfaces are limited in 2D plane of conventional air cathodes, which limits the electrochemical kinetics and the commercialization of zinc-air batteries.
· Without changing the catalyst materials, improve the power density of zinc-air batteries only through the structural design of air cathodes.
· Using non noble metal catalysts, reach a power density more than 100 mW·cm-2 for zinc-air battery.
· Designed and fabricated air cathodes with novel structures which make three-phase
reaction interfaces expand from 2D plane to 3D zone.
· Used the method of SEM, XRD and EDS to characterize the material properties of MnO2 as catalysts.
· Evaluated the effect of the design process on the hydrophobicity of air cathode through contact angle test.
· Verified the electrochemical performances by LSV, EIS and constant current discharge.
· A peak power density of 120 mW·cm-2
for zinc-air battery is achieved with MnO2 as catalysts when the loading is 1.0 mg·cm-2.
· Compared with previous reports, this work shows higher power density per catalyst loading.
The bifunctional electrocatalyst has an important influence on the power output and cycle life of
rechargeable zinc-air batteries. Cobalt oxides, especially Co3O4, have attracted much attention due to
their high catalytic activity for oxygen evolution reaction (OER). It is difficult to improve the catalytic
activity of oxygen reduction reaction (ORR) for rechargeable zinc-air batteries.
· Design a new type of Co3O4-based catalyst, which the catalytic activity was higher than that of Co3O4, and the cycle life of the assembled zinc-air battery was not significantly decreased.
· Prepared Carbon-coated oxygen vacancies-rich Co3O4 nanoarrays by hydrothermal
reaction, plasma treatment and calcination.
· Used the method of SEM, XRD, TEM, EDS, RDE and EPR to characterize the material properties.
· Assembled A Zinc Air Flow Battery.
· Used the method of RDE and full battery test to characterize the catalytic activity.
· The peak power density of zinc-air battery with proposed catalysts was 52.8% higher than that of untreated Co3O4.
· Coated carbon protected vacancies and prolonged cycle life to 358 h.
Among all kinds of batteries, magnesium air battery has obvious advantages as emergency rescue battery. At present, considering the emergency use of magnesium air battery, there are still two problems to be solved. One is that traditional magnesium anode materials are prone to self corrosion hydrogen evolution reaction, which leads to low anode efficiency and underutilization; Second, the battery structure is relatively complex, which is not designed to meet the needs of lighting and power supply for electronic equipment in emergency state, or it is large in volume and heavy in quality, which is still inconvenient due to the lack of resources such as disaster relief, transportation cost, personnel safety and convenient carrying.
Considering a magnesium air battery system, some structures are designed to simplify electrolyte replacement. At present, three schemes are designed and discussed. The first solution is to design a kind of weight packaging. According to the cycle of each use, the weighed NaCl powder is packaged according to the weight. In the second solution, theoretical calculation is carried out to make the replacement cycle of magnesium alloy plate consistent with that of electrolyte. In the third solution, the process of electrolyte configuration is simplified. The NaCl powder is wrapped with cotton wadding, and then compressed into a thin sheet by applying a certain pressure. At this time, there is a large amount of NaCl powder in the thin sheet, and the pores of the thin sheet are small, which can prevent NaCl powder from leaking out of the thin sheet.
