A Rational Reconfiguration of Electrolyte for High‐Energy and Long‐Life Lithium–Chalcogen Batteries

Abstract

Lithium–chalcogen batteries are an appealing choice for high‐energy‐storage technology. However, the traditional battery that employs liquid electrolytes suffers irreversible loss and shuttle of the soluble intermediates. New batteries that adopt Li+‐conductive polymer electrolytes to mitigate the shuttle problem are hindered by incomplete discharge of sulfur/selenium. To address the trade‐off between energy and cycle life, a new electrolyte is proposed that reconciles the merits of liquid and polymer electrolytes while resolving each of their inferiorities. An in situ interfacial polymerization strategy is developed to create a liquid/polymer hybrid electrolyte between a LiPF6‐coated separator and the cathode. A polymer‐gel electrolyte in situ formed on the separator shows high Li+ transfer number to serve as a chemical barrier against the shuttle effect. Between the gel electrolyte and the cathode surface is a thin gradient solidification layer that enables transformation from gel to liquid so that the liquid electrolyte is maintained inside the cathode for rapid Li+ transport and high utilization of active materials. By addressing the dilemma between the shuttle chemistry and incomplete discharge of S/Se, the new electrolyte configuration demonstrates its feasibility to trigger higher capacity retention of the cathodes. As a result, Li–S and Li–Se cells with high energy and long cycle lives are realized, showing promise for practical use.

Formulating the Electrolyte Towards High‐Energy and Safe Rechargeable Lithium–Metal Batteries

“…To verify changes in molecular structures of DOL, Fourier transform infrared (FTIR) spectra were collected from the precursor solution and HSLE. According to Figure 2d,t he peaks at 1100, 1223 and 2900 cm À1 are separately attributed to stretching vibration of -C-O-, -C-O-H and -CH 2 -, [16] indicating formation of characteristic polymer group (e.g., -CH 2 -O-CH 2 -CH 2 -O-H) in the solidified electrolyte.…”

Recent Progress in High‐Performance Lithium Sulfur Batteries: The Emerging Strategies for Advanced Separators/Electrolytes Based on Nanomaterials and Corresponding Interfaces

“…The polymer electrolyte was beneficial to hamper shuttle of soluble discharge intermediates, while the liquid electrolyte preserved in the interior of the cathode supported rapid Li + transport and high utilization of active chalcogen molecules. [7] Compared with alone electrolytes, the addition of inorganic additives to the electrolyte results in greater viscosity, higher surface activation energy, lower lithium ion transmission, and slower electrochemical reactions.…”

Modulating the lithiophilicity at electrode/electrolyte interface for high-energy Li-metal batteries

“…The unsatisfactory performance of Li-metal anodes originates from the unstable structural and chemical evolutions at the anode/electrolyte interface, which include infinite volume variation, the formation of unstable solid electrolyte interphases (SEIs) and the growth of Li dendrites. To improve the performance of Li-metal anodes, efforts have been made to regulate the chemical compositions and structures of the electrolyte [1][2][3] and the Li-metal anode [4] to reshape the SEI [5,6] and to rebuild the current collector [4,[7][8][9] . The lithiophilicity of electrolytes at the anode/electrolyte interface was studied as it significantly affects the uniformity of Li deposition/dissolution at the interface.…”