Lithiophilic Covalent Organic Framework as Anode Coating for High‐Performance Lithium Metal Batteries

Abstract

The growth of disorganized lithium dendrites and weak solid electrolyte interphase greatly impede the practical application of lithium metal batteries. Herein, we designed and synthesized a new kind of stable polyimide covalent organic frameworks (COFs), which have a high density of well‐aligned lithiophilic quinoxaline and phthalimide units anchored within the uniform one‐dimensional channels. The COFs can serve as an artificial solid electrolyte interphase on lithium metal anode, effectively guiding the uniform deposition of lithium ions and inhibiting the growth of lithium dendrites. The unsymmetrical Li||COF‐Cu battery exhibits a Coulombic efficiency of 99% at a current density of 0.5 mA cm‐2, which can be well retained up to 400 cycles. Meanwhile, the Li‐COF||LFP full cell shows a Coulombic efficiency over 99% at a charge of 0.3 C. And its capacity can be well maintained up to 91% even after 150 cycles. Therefore, the significant electrochemical cycling stability illustrates the feasibility of employing COFs in solving the disordered deposition of lithium ions in lithium metal batteries.

Covalent Organic Framework-Based Materials for Advanced Lithium Metal Batteries

“…Through a comparative analysis of the surface morphology of the electrode postcycling (Figure 3cf), the LZU1-COF layer demonstrates a significant capability in suppressing the proliferation of lithium dendrites. Similarly, Wu et al 115 synthesized COFs with polyimide organic functional groups, named HAHATN-PMDA-COF. It has a 2D triangular structure and a uniform one-dimensional channel (Figure 3g), which provides a way for Li + migration and greatly improves the amount of Li + migration like Figure 3h.…”

“…(h) Side view of a graphic presentation of HAHATN-PMDA-COF (nitrogen, blue; carbon, green; oxygen, red; hydrogen, white). Reprinted with permission from ref . Copyright 2024 Wiley-VCH.…”

Advances in nanoporous materials for next-generation battery applications

“…While using nanoporous materials in batteries to suppress the growth of Li dendrites, 18,20,37–42 there has been great progress in inhibiting the side reactions between liquid electrolytes and the Li anode. The uniform nanoporous separator, designed and prepared by our group, not only prevented lithium dendrite formation over extended cycling periods in both Li–Li symmetric batteries and high-voltage lithium metal batteries that used LiNi 0.6 Mn 0.2 Co 0.2 O 2 as the cathode, but also effectively inhibited side reactions, allowing the Li anode to maintain its original metallic lustre.…”

Fluorinated Conjugated Polymers Enabled Enhanced Detectivity in Organic Near-Infrared Photodetectors

“…Conjugated polymers (CPs) are an important component of bulk-heterojunctional OPDs in which structure modification of CPs can adjust their molecular aggregation, charge transport, and optoelectronic properties. − CPs possess unique semiconductor properties, and understanding how to control their optoelectronic performance is critical for designing CPs with improved photoresponse characteristics. A large number of studies in the field of organic electronics show that the halogenation strategy is an ideal method to improve the optoelectronic properties of CPs. − Fluorine (F) substitution, in particular, can not only adjust the energy level structure of CPs but also improve their crystallinity, trap density, and mobility. − Bai et al found that in D-A-type CPs, fluorination of electron-donating units can suppress density of trap states in the active layer, effectively enhancing performance of OPDs . Additionally, Park et al studied the effect of fluorinated alkyl chains in CPs on J dark and D* of OPDs.…”