Poly(Ether-Ester)-Based Solid Polymer Electrolytes with High Li-Ion Transference Number for High Voltage All-Solid-State Lithium Metal Batteries

Abstract

Considering the lower room temperature ionic conductivity, Li-ion transference number, and narrow electrochemical stability window in all-solid-state polymer electrolytes (ASSPEs)-based lithium metal batteries (LMBs), it is of particular necessity to find plausible strategies to accomplish these issues. In this paper, poly­(ε-caprolactone-co-1,5-dioxepan-2-one) (PDCL)-based poly­(ether-ester) ASSPEs have been successfully fabricated by the random ring-opening polymerization of cyclic CL and DXO. The PDCL-SPE exhibits a high ion conductivity of 3.54 × 10–5 S cm–1 at 30 °C with a high Li-ion transference number (0.62) and a superior electrochemical stability (5.1 V). FT-IR spectra confirm the synergistic effect of ether and carbonyl of ester from the main chain of PDCL, which is superior to the dissociation of lithium salts and facilitation the motivation of lithium ions. Furthermore, the assembled LiFePO4/PDCL-SPE/Li batteries displayed low interfacial resistance, Li dendrite suppression, high specific capacity, and excellent cyclic performance (capacity retention of 85% after 200 cycles at 0.1 C). The high-voltage LiNi0.5Co0.2Mn0.3O2/PDCL-SPE/Li batteries also exhibits good cycling performance and durability.

Solid-state polymer electrolytes in lithium batteries: latest progress and perspective

“…The charge/ discharge voltage curves for Li/PDCL40-SPE/Li remained stable with a low polarization potential (0.04 V). 128 P. Nkosi et al added LLZO at different levels to improve composite electrolyte performance with LiFePO 4 cathode interfacial contact, achieving a conductivity value of 1.31 × 10 −4 S cm −1 at 60 °C (Fig. 8d).…”

Designing Polymer Electrolytes via Ring‐Opening Polymerization for Advanced Lithium Batteries

“…[35] It can also be seen that in order to improve the shortage of SPEs prepared by a single monomer, researchers have also tried to copolymerize several ring monomers to improve the performance of the electrolyte. [82] For example, through the ROP of 1,3-dioxolane and 1,3,5-trioxane, the lithium-ion migration number of the corresponding SPE has been significantly improved. [83] A comprehensive analysis of Table 4 shows that a very rich variety of monomers has been developed, and a series of SPEs with tunable properties have been obtained by ring opening of monomers triggered by different types of initiators.…”

“…By random anionic ROP of 𝜖-caprolactone and 1,5-dioxepan-2one, Chen et al synthesized poly(𝜖-caprolactone-co-1,5-dioxepan-2-one) (Figure 18d), which corresponds to an electrolyte with room temperature ionic conductivity of 3.54 × 10 −5 S cm −1 , a lithium-ion transfer number of 0.62, and an electrochemical window of up to 5.1 V. The electrolyte is also compatible with LiNi 0.5 Co 0.2 Mn 0.3 O 2 (NCM523) electrodes (Figure 18d). [82] It can be seen that the performance of polyester-based electrolytes has been greatly improved after much effort. However, there is still a lack of attention on the modulation of molecular microstructure.…”

“…[ 35 ] It can also be seen that in order to improve the shortage of SPEs prepared by a single monomer, researchers have also tried to copolymerize several ring monomers to improve the performance of the electrolyte. [ 82 ] For example, through the ROP of 1,3‐dioxolane and 1,3,5‐trioxane, the lithium‐ion migration number of the corresponding SPE has been significantly improved. [ 83 ]…”

Aliphatic Hyperbranched Polycarbonates Solid Polymer Electrolytes with High Li‐Ion Transference Number for Lithium Metal Batteries

“…[1][2][3][4][5] Elevated energy density can be achieved through the selection of high-capacity electrode materials, such as Li metal, and increasing the operational voltage of the battery. [6][7][8][9][10] Meanwhile, enhancing battery safety relies on the adoption of solid-state electrolytes. Solid polymer electrolytes (SPEs), renowned for their lightweight composition, suitable mechanical strength, and robust interface stability with electrodes, can simultaneously act as separators and electrolytes.…”