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A special polymer material for battery cathodes has been developed by Russian scientists, which makes it possible to reduce the charging period to many seconds while increasing their density along with their service life. Batteries with modern cathodes would be able to run for up to 70 years while maintaining roughly one third of their power.
Batteries are going to get better
Russian experts from the Russian Chemical-Technological University of Skoltech. New materials based on polymers have been developed by DI Mendeleev (RCTU) and the Institute for Chemical Physics Problems (IPCP) for their use as a cathode in modern batteries. The researchers tested them as part of special lithium two-ion batteries, and obtained ultra-fast batteries that charge in a couple of seconds at the output.
The use of new cathode materials not only shortened the time taken to recharge the battery, but also greatly increased its operational life. These batteries can survive up to 25 thousand recharging cycles.
Potassium two-ion batteries can also be made, according to the authors of the latest technology, using cathodes as their basis, in which costly and very non-environmentally friendly (even at the production stage) lithium is replaced by more inexpensive and less rare-earth and toxic potassium.
Two polymers, and the new battery type
Two new branch polymers, a copolymer of dihydrophenazine and diphenylamine and a copolymer of dihydrophenazine and phenothiazine, were synthesized at once by experts from the RCTU, IPHF and Skoltech. Tests have demonstrated that the job is much better done by the first polymer – he was the one who made it possible in a few seconds to completely charge the battery. In addition, the battery can withstand up to 25,000 recharge cycles while maintaining up to a third of its power without using it. Experts have estimated that such a battery could last up to 70 years under standard operating conditions.
The scientists used metallic lithium as the anode, but they also experimented with potassium. An improved energy capacity of up to 398 Wh/kg was demonstrated by batteries with an anode made of this substance and a dihydrophenazine and phenothiazine copolymer as a cathode. A 1.5-2 times lower density was shown by lithium batteries of the same cathode – from 200 to 250 Wh/kg.
The cathode materials developed by the researchers are focused on aromatic amines that are polymeric. Their characteristics include, among other aspects, the capacity to synthesize different organic compounds from them. As for two-ion batteries, unlike traditional lithium-ion batteries, both anions and cations of the electrolyte are involved in the electrochemical processes within them. The multiple increase in the charge speed is directly influenced by this.
Our group has also done work on polymer cathodes for high-speed, high-capacity batteries that can be charged and discharged in a few seconds. Linear polymers have previously been used, among others, in which each monomeric unit forms bonds with just two neighbors, and we have continued to explore new branched polymers in this work, in which each unit can form bonds with at least three other units. They shape volumetric mesh structures that provide faster electrode process kinetics,’ noted a Skoltech graduate student, Philip Obrezkov, the first author of the work. “Batteries can be charged and discharged even faster with electrodes made from these materials,” he said.
The inventors did not define when, according to their predictions, it would be possible to start mass production of batteries using the polymer cathodes they developed. There are, meanwhile, a range of promising developments in Russia that can boost new batteries and can compete with the brainchild of RCTU, IPHF and Skoltech employees.
MISIS experts also have another solution to lithium batteries, which contains neither sodium nor potassium – only a cannabis plant that grows in abundance in several regions of Russia. For their conversion into carbon content and then into electrodes, scientists have developed special methods for their production, including exposure to hydrochloric acid and carbon dioxide saturation. They suggest not to produce batteries, but supercapacitors with an electrode from hogweed stalks.
In laboratory conditions, the existing technology of turning hogweed into supercapacitor electrodes was tested, and the experiment was a success. However, as in the case of polymer cathodes and potassium batteries authored by RCTU, IPHF and Skoltech physicists, the authors do not define the conditions of this idea’s commercialization.