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Organic batteries have attracted much attention because of their flexibility, high-power densities, and highly designable structures of electrode-active materials. The electrochemical potential of the batteries can be modulated using different organic redox species or by structural modification of the redox unit centers. In this study, the electrochemical potential of lithium organic radical batteries is modulated, without the structural modification of the redox unit centers. Two different crown ethers, 12-crown-4 (12C4) and 15-crown-5 (15C5), served as electrolyte additives to increase the electrochemical potential of the batteries. An average discharge voltage can be increased to 3.90 V through the electrolyte system using various concentrations of the electrolyte salt and crown ethers. The addition of 1 equiv of 12C4 to the Li|0.25 M LiClO4-ethylene carbonate/diethyl carbonate (= 1/1, v/v|poly­(2,2,6,6-tetramethylpiperidin-1-oxy-4-yl methacrylate) cells significantly improved the capacity retention up to 21% after 300 cycles at a current rate of 3C. Furthermore, the structures and system energies of the lithium–crown ether complexes are investigated using density functional theory calculations.

Two thermoplastic triblock copolymers of poly(εcaprolactone)-based acidic (PCL-A) and basic (PCL-B) polymers are synthesized by atom transfer radical polymerization. PCL-A and PCL-B are sequentially electrospun on a sulfur electrode and then ionically cross-linked by an acid−base reaction via hot pressing at 70 °C, which is confirmed by infrared (IR) spectroscopy. The cross-linked PCL-A/PCL-B-electrospun sulfur electrode is assembled as a lithium−sulfur battery with an asymmetric gel polymer electrolyte. The cross-linked polymer is swollen by a liquid electrolyte to form an asymmetric gel polymer electrolyte. The cyclic voltammetry results indicate that the asymmetric gel polymer electrolyte can suppress the dissolution of lithium polysulfides (Li 2 S n ) into the electrolyte. Furthermore, the lithium−sulfur battery with the asymmetric gel polymer electrolyte exhibits enhanced cycle-life performance.