The hottest low-cost high-performance potassium io

2022-10-01
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The birth of low-cost high-performance potassium ion full battery

the modern society of informatization and automation continues to progress, in which electrochemical energy storage devices are developed, so the two must be distinguished and play an important role. Since the 1990s, with the commercial application of lithium-ion batteries, lithium-ion batteries have become a part of our life since the 21st century. Lithium-ion battery portable devices and power cars have been everywhere in every corner of life. However, unlike other commercial products, the more they are sold, the cheaper they will be. The scarce lithium resources make the cost of lithium-ion batteries continue to rise in the future. It is an urgent problem to find an alternative low-cost electrochemical energy storage device. The electrochemical properties of potassium and sodium are similar to lithium, and the earth is rich in reserves, which is expected to replace lithium-ion batteries in the future

the research of sodium ion battery has made great progress in recent years, but its standard electrode potential (-2.71 V, vs she.) And the large ion radius limit, making the current energy density and power density of sodium ion batteries still have a large gap with lithium-ion batteries. Standard electrode potential of potassium (-2.93 V, vs she.) Closer to lithium (-3.04 V, vs she.), Because the ion radius of potassium ion and sodium ion is larger than that of lithium ion, although the energy density is less than that of lithium ion, the current research on potassium ion negative carbon material shows that the power density of potassium ion battery is higher than that of sodium and closer to that of lithium ion battery, and the magnification performance is also better. However, at this stage, the research on potassium ion cathode materials is very little, most of which use aqueous solution as electrolyte, and the voltage window is limited. Recently, a low-cost dye nanoparticle, Prussian blue, was prepared by the research group of Professor Lei Yong of ilmnau University of technology in Germany and the research group of Shanghai University. As a potassium ion cathode material, its electrochemical properties in organic electrolyte were described in detail. At the same time, using it as a potassium ion cathode material, a high-performance potassium ion full battery was matched for the first time. The test results show that Prussian blue, as a potassium ion cathode material, presents a high discharge platform (3.1 – 3.4 V), a stable reversible specific capacity. At the charge and discharge rate of 50 ma/g, it still has a cycle specific capacity of 73.8 MAH/g, and the degradation rate is very slow, only 0.09% per cycle. At the same time, by analyzing the electrochemical storage mechanism of Prussian blue molecule, they found that this framework molecular structure is very conducive to the storage and release of potassium ions with large radius, and its main active site is c-fe Ⅱ/fe Ⅲ. Finally, they designed and matched the potassium ion full battery for the first time through this positive material and combined with the commercial super P as the negative material. The full battery has a reversible specific capacity of 68.5 mah/g at a charge and discharge rate of 100 ma/g, and has a long cycle life, After 50 cycles of charge and discharge, it still has 93.4% specific capacity, which can be customized according to the specific conditions of the user's local area. For potassium ions with large radius, such a breakthrough is invaluable

the research of low-cost Prussian blue dye as potassium ion cathode material and the matching design of the whole battery make lithium ion battery find a better and suitable substitute. This research provides a broad prospect for the research and commercial application of potassium ion battery in the future. This paper has been published in advanced functional materials (DOI: 10.1002/adfm.) to make it more scientific, And make a brief introduction on the current back cover

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