Robust Microporous Naphthalenediimide-Based Hydrogen-Bonded Organic Framework for High-Performance Lithium-Ion Storage

Abstract

Hydrogen-bonded organic frameworks (HOFs) have attracted extensive attention in recent years due to their advantages of large surface area, high crystallinity, and high porosity. Unfortunately, their application in lithium-ion storage remains difficult to achieve because hydrogen bonds are prone to dissociation in the electrolyte, which degrades the integrity of the structure. This problem can be overcome with a naphthalenediimide-based HOF (NDI-HOF), designed and synthesized using the building block N,N′-bis[(1-oxidopyridin-1-ium-4-yl)methyl]-1,8:4,5-naphthalene tetracarboxdiimide (DPNDI-2O). The multisite hydrogen bonds and π–π interactions regulated by the DPNDI-2O molecule endow this material with unique chemical and thermal stability. It has a very low solubility in most nonpolar and polar organic solvents and can maintain its crystallinity, thus enabling its electrochemical application. This stable HOF material shows a high capacity and outstanding cycling stability for Li⁺ ion storage. The material retained a specific capacity of 225 mAh·g^–1 over 1000 cycles at a 400 mA·g^–1 current density. This enhanced capacity and outstanding cycle life stem from the synergistic combination of numerous active sites and structural robustness. It maintained a specific capacity of 225 mAh·g^–1 after 1000 cycles at 400 mA·g^–1. The enhanced specific capacity and superior cycling performance originate from the synergistic interplay between the abundant active sites and the robust structure. Molecular simulations identified Li⁺ ion binding locations in the material structure and suggested that intermolecular diffusion occurs with a comparatively low energy barrier.