The team develops a framework for rechargeable lithium metal batteries with high energy density, long lifecycle

Research conducted by the Vilas Pol Energy Research Group (ViPER) of Purdue University shows the prospect of developing rechargeable lithium-metal batteries with high energy density and addressing electrochemical oxidation instability. of ether-based electrolytes.

The study was published in the February 10 issue of the journal natural communication. Zheng Li, a graduate research assistant at the Davidson School of Chemical Engineering, is the lead author.

ViPER Group’s focus is on the design and manufacture of high-capacity materials for safe next-generation lithium-ion, lithium-sulfur, sodium-ion, solid-state and ultra-low temperature battery systems. than.

“The rapid development of energy storage technologies to reduce proposed carbon emissions targets and huge demand for energy storage systems also exist in the electric vehicle and consumer electronics markets. They call for next-generation Li batteries to have higher energy density with enhanced safety,” said Vilas Pol, a professor of chemical engineering who has led Purdue’s flagship labs for the fabrication. battery making, electrochemical and thermal safety testing since 2014.

Replacing conventional graphite anode materials with high-energy lithium metal is a very promising approach. However, this kind of “holy grail” anode material suffers from intractable disadvantages such as low recyclability and safety, etc.

“From a fundamental research perspective on new LMB technologies, it is important to meticulously develop the right liquid electrolyte chemistry that works with promising anodes and cathode,” says Pol. .

In their study, the researchers demonstrated that a low-concentration ether-based electrolyte can successfully endure the long-term high-voltage (4.3 V) operation of actual LMB under extreme conditions. possible configuration in the industry, when using highly nonpolar dipropyl ether as the electrolyte solvent.

“Recognizing the long-term cycling of the Li metal anode and the high-voltage cathode simultaneously with a diluted ether-based electrolyte was the main challenge in this study,” Li said. “Ethers have poor oxidation stability although they have reasonable compatibility with Li metal anodes. Therefore, our goal was to extend their high voltage capabilities. From Element Levelwe confirmed an essential correlation between the dissolution behaviors of diluted ether-based electrolytes and their performance on high voltage electricity the positive electrode.”

The correlations were further explained through detailed classical molecular dynamics (MD) simulations and density functional theory (DFT) calculations along with multimodal experimental analyses. It has been shown that soluble conformational modification of ether-based electrolytes can rearrange the decomposition order of the soluble species and selectively form a strong defense on the surface. cathode surface. It also regulates the composition of the surface electrical bilayer to prevent oxidation of the ether.

This unique kinetic inhibition method differs from conventional strategies such as using extremely high concentrations of electrolytes or introducing molecular fluorination to improve electrolyte stable, greatly increase the battery cost. LMB developed by ViPER team expected to improve 40% power densitycompared to conventional Li-ion batteries.