Multi-redox covalent organic frameworks for aluminium organic batteries

Aluminium ion batteries utilizing advanced organic electrode materials have attracted increasing attention in achieving the energy transition to net zero carbon emissions. Nevertheless, extensive studies have focused on structural innovations to enhance electrochemical performance while overlooking inherent constraints, such as frustrating aggregation and stacking, stemming from organic materials. These constraints result in compromised conductivity, sluggish charge storage kinetics, and suboptimal stabilities. Therefore, this study demonstrates a controlled nuclear-growth strategy for the landscaping of redox-active covalent organic frameworks (COFs) featuring multiple C=O and C=N groups. Theoretical simulation and ex-situ analysis were applied to uncover the pivotal roles of the C=O and C=N as active sites for the reversible storage of AlCl²⁺ ions. Employing an interfacial crystallization strategy, we further orchestrate the vertical stacked growth of COF on multiwall carbon nanotubes, which yields significant improvements in battery performance, including a high capacity of 150 mAh g⁻¹ at 200 mA g⁻¹, excellent rate capability, and an exceptional cycling lifespan of 140 mAh g⁻¹ over 2400 cycles at 1 A g⁻¹, along with 10,000 cycles exhibiting ∼100 % Coulombic efficiency at 2 A g⁻¹. This study paves the way for a new avenue in achieving precise structural engineering of COF materials, promising considerable potential for energy storage applications.