What are the important parameters that restrict the practical application of lithium oxygen batteries?

Lithium-air battery technology has always been a hot technology that people pay attention to. Its high theoretical energy density has been expected by everyone, but the problems and challenges of this technology have always been very many. More people in the industry pointed out: "Lithium air cells combine the shortcomings of fuel cells and lithium-ion batteries" and "too many reaction side reactions" and other issues. Here, I also want to make a brief outlook on the future of lithium-empty battery technology based on the development of this article and the industry's expectations for battery technology.

The protective layer is added, and this layer is actually at the cost of increasing the internal resistance(increasing the initial polarization) in exchange for stability and cyclic life. Therefore, we can see that under the condition of low reaction current, the polarization voltage difference of the first week cycle is large(0.88 V), and the performance of the system is further attenuated as the cycle progresses, 1.3 V after 50 weeks, and 1.62 V after 550 weeks. In contrast, lithium-ion batteries that are commercial under small currents often have only 0.1 V of overpotential, which still clearly shows the distance from the practical application of lithium-ion battery technology.

The energy conversion efficiency of such a large polarization of lithium empty batteries is actually only 60 to 70 %, which is still a very unacceptable data for practical use, especially for power batteries. In addition, as with many nanometer related research directions, the research results of lithium empty batteries are rarely reported for volumetric energy(Wh/L), and this parameter is also a crucial parameter for the power cell field. Again quoted from Professor JEFFDAHN's report, which pointed out that the theoretical volume of lithium-empty batteries is 3400 Wh/L(about three times that of lithium-ion batteries), so although it has an advantage in this regard, it is not as large as it was imagined. If you consider the excess lithium required for lithium negative electrode applications, the advantage may be even smaller. Therefore, the practical application of lithium empty technology also requires the Advancement of lithium metal electrode technology.

The volume-to-energy comparison of lithium and lithium ion batteries(theoretical value), extracted from Jeff Dahn's report "ElectricallyRechargeableMetal-BatiesComparedtoAdvancedLithium-Batteries"

In addition, in this article, there does not seem to be any reference to the mass ratio energy(in Wh/kg). You know, for lithium, we're looking at high specific energy -- because the other properties of lithium are actually not ideal. Therefore, we also very much look forward to the author's further work to give us information and guidance in this regard. In addition, the successful use of secondary lithium-empty batteries still can not get rid of the dependence on suitable ORR/OER catalysts, and it is even more difficult to find materials that can perform these two functions at the same time.

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