20,000 times! Lithium battery performance broke records again, new coating help break through two bottlenecks

As we all know, lithium-ion batteries are widely used in contemporary society with their excellent energy density. Although it is easy to generate dendrite and SEI membranes in the process of recycling, which damages battery performance, failure and even risk fire, no perfect new technology can replace them.

 Scientists have long been doing their best to find new ways to overcome these bottlenecks. Researchers at the University of Arkansas (the University of Arkansas) have reportedly developed a new lithium-containing cross-linked polymer material. The new material, called LiGL (GL= panol / glycerin), helps solve two of the problems with the commercial lithium metal anode.

 It is said that this LiGL polymer film has excellent properties, which can effectively prevent the growth of dendrite and SEI film formation of lithium metal anode, and realize the long-term stable cycle performance of lithium electrode. The results were recently published in the journal Progress in Energy Materials (Energy Material Advances).

To date, various technical strategies have been reported to solve the problems of lithium-negative electrodes, such as three-dimensional (3D) lithium-bearing frames, electrolyte additives, solid electrolytes, and surface coatings."Surface coating remains a simple and effective approach in these efforts," said Xiangbo Meng, the corresponding author of the research paper and a professor at the Department of Mechanical Engineering at the University of Arkansas.

"Molecular layer deposition (MLD) has recently become a new research direction, first practiced in 2018," Meng said. " These polymer films, precisely synthesized by MLD, have better flexibility than inorganic films, helping to provide better protection and improve the performance of lithium anode.”

Meng and his team have developed three lithium-ion polymer MLD processes and studied the protective effects of these polymer film coatings in an attempt to achieve long-term stable cycle performance and barely form SEI of lithium dendrites and lithium electrodes.

"In this work, we developed for the first time a new lithium-containing cross-linked polymer material, a lithium that produces excellent protection against the lithium metal anode," Meng said."We found that LiGL lithium one can be used as a special polymer protective film covering the lithium metal anode.”

According to him, the LiGL MLD shows an excellent protective effect on the lithium electrodes, which significantly inhibits the lithium dendrite and reduces SEI formation. Computational simulations and experiments also show that the MLD LiGL membrane is electrically insulating and ionically conductive.

 In their study, experimental data showed that lithium electrodes coated with LiGL lithium ones have excellent cycle stability. Under the condition of current density of 5 mA / cm2 and area capacity of 1 mAh / cm2, the number of lithium stripping or electroplating cycles in Li / Li symmetric cells can reach more than 13,600 times without failure.

At present, the updated results show that the fault-free cycle capacity has increased to more than 20,000 lithium stripping / plating cycles (more than 10,000 hours or more than a year). It is understood that this is the best cycling performance reported. Therefore, MLD LiGL technology has laid a technical way to solve the problem of lithium anode.

"The properties of LiGL coatings, such as mechanical properties and electrical conductivity, are the basis for their excellent protection of lithium-metal electrodes," Meng said. " The new LiGL we developed represents a simple and effective solution to the existing problems of lithium anode and may pave a technically viable route for lithium-metal batteries.”