Heteroporous Donor-Acceptor Covalent Organic Framework Cathode for High-Rate-Capacity Lithium-Ion Battery.

Covalent organic frameworks (COFs), a conspicuous porous material, harvest great promise for rechargeable batteries, owing to well-defined pore structure and structural precision. However, designing high-rate-capacity COF cathode by balancing ions diffusion kinetics and electron transport kinetics based on the framework and pore chemistry remains a challenge. Here, a heteroporous donor-acceptor (D-A) engineering is proposed to design one novel kind of COF (HDA-COF) with optimized electronic conductivity (σ) and ionic conductivity (σ). The heteroporous D-A framework featuring with triangle-like micropores for promoted electron transport and enlarged hexagonal-like mesopores for facilitated ions diffusion rate. HDA-COF demonstrates high compatibility with high σ and σ verified by the combination of experimental results and theoretical calculations. Notably, HDA-COF displays favorable fast-charging performance with 104 mAh g (277 Wh kg, 5 A g) and shorter charge time (75 s), maintaining steadily cycling for 1000 cycles at 5 A g. Also, it delivers high discharge capacity of 259 mAh g (627 Wh kg, 0.05 A g). This work offers in-depth insights in constructing high-rate-capacity COF cathode by synchronously optimizing σ and σ within a heteroporous D-A engineering.