Solution-Processable Covalent Organic Framework Electrolytes for All-Solid-State Li–Organic Batteries

Abstract

Solid electrolytes (SEs) are milestones in the technology roadmaps for safe and high energy density batteries. The design of organic SEs is challenged by the need to have dynamic structural fluidity for ion motion. The presence of well-ordered one-dimensional (1D) channels and stability against phase transition in covalent organic frameworks (COFs) render them potential candidates for low-temperature SEs. Herein, we demonstrate two milestones using hydrazone COF as an SE: it achieves an ion conductivity of 10–5 S cm–1 at −40 °C with a Li+ transference number of 0.92 and also prevents the dissolution of small organic molecular electrode in all-solid-state batteries. Using 1,4-benzoquinone as the cathode, a lithium battery using hydrazone COF as a SE runs for 500 cycles at a steady current density of 500 mA g–1 at 20 °C. Considering that hydrazone COF is readily amenable to large-scale production and facile post-synthetic modification, its use in an all-solid-state battery is highly promising.

2D Materials for All‐Solid‐State Lithium Batteries

“…When the 2D LiCON is applied in the ASSLB, it is stable for 500 cycles at 500 mA g −1 at 20 °C. [178] In addition, with the unique properties of 2D COF, Sun et al fabricated ultrathin SSEs with a thickness of 7.1 µm, which contributes to the high energy density of the battery. [179] Adv.…”

A physicochemical introspection of porous organic polymer photocatalysts for wastewater treatment

“…Recently, Loh et al reported a post-synthetic solution-processable COF stacking approach to significantly mitigate this issue. 86 Another common poly-crystalline defect observed in ordered POPs is crystal cracking. 87 Usually, crystals that grow along the xy-plane often manifest such defects resulting in the creation of added grain boundaries (Fig.…”

Progress of Solid‐state Electrolytes Used in Organic Secondary Batteries

“…The layered conjugated organic solid electrolyte used in lithium/benzoquinone (BQ) secondary batteries showed influentially against the dissolution of BQ and improve cycle stability. [58] The structure of the lithiated covalent organic nanosheet (LiCON-3) was displayed in Figure 5a, its ionic conductivity at 20 °C and À 40 °C were 3.21 × 10 À 5 S cm À 1 and 9 × 10 À 6 S cm À 1 (Figure 5b), respectively. The Li + transference number was 0.92 and the electrochemical stability window was 4.3 V. Assembling the Li/LiCON-3/BQ solid battery and performing 500 cycles at 20 °C with a current density of 500 mA g À 1 (Figure 5c), the capacity remained 87.7 % of its initial specific capacity.…”

“…[60,61] For SPEs, replacing the OLEs could Copyright 2020, American Chemical Society. [58] elevate the safety of the batteries. Nevertheless, their room temperature ionic conductivity is generally low and the increase in ionic conductivity is often accompanied by a decrease in mechanical strength.…”