Hydrophobicity of 2-((8-hydroxyoctyl)oxy)ethyl-sulfanetrione in conducting solid polymer electrolyte boosting the electrochemical performance of lithium metal batteries

Rechargeable solid-state lithium metal battery (LMB) is an important next-generation energy storage technology . Anion chemistry of sulfonates plays a vital role in dictating the electrochemical performance of conducting solid polymer electrolytes (CSPEs). CSPE is a crucial need for LMB, although, simultaneously achieving high ionic conductivity and greater cycling performance in LMBs is a huge challenge. Herein, we design and synthesize new sulfonate anions 2-((8-hydroxyoctyl)oxy)ethyl-sulfanetrione (HOEST) and 2-(4-hydroxybutaoxy)ethane-sulfonate (HBES), and a series of CSPEs via coupling of these anions by tetraethyl orthosilicate for LMBs. HOEST-V CSPE consists of HOEST with PVDF polymeric matrix that delivers higher ionic conductivity (3.17 × 10 −3  S cm −1 ) and outstanding cyclability (152 mAh g −1 ) at 25 °C for 1100 cycles. The excellent stability over 500 h of Li stripping/plating, high apparent diffusion coefficient (0.07177), and low activation energy (5.0251 Kj/mol) of HOEST-V impede the lithium dendritic growth for good compatibility with electrodes. The hydrophobic alkyl spacer of HOEST-V with anionic species and hydroxyl wing associated with ether spacer can dissociate and augment the Li + ions mobility resulting from their intramolecular and intermolecular interactions , hydrogen bonding , and ion-dipole interaction. This strategy is promising and opens a new avenue for developing safe and high-performance CSPEs in future.