Two-Dimensional Crystalline Alkyne-Rich Conjugated Carbonaceous Framework for Extremely Fast-Charging Lithium-Ion...

The development of high-quality conjugated carbonaceous materials with fast mass transport kinetics is important for fast-charging lithium (Li)-ion batteries (LIBs). Here, we report a "molecular locking-weaving" strategy to synthesize 2D alkyne-rich Li carboxylate (LC) conjugated carbonaceous framework (LC-ACF). Large-area ultrathin LC-ACF possesses high crystallinity, ordered stacking, and intrinsic mesoporous structure, creating well-aligned and LC-bridged fast Li-ion diffusion channels. The incorporation of LC groups significantly changes the electronic structure of the conjugated framework to improve surface charge and electronic conductivity, endowing LC-ACF with promoted electrokinetic effects to boost Li-ion transport kinetics. Consequently, LC-ACF shows exceptional fast-charging capability, achieving high capacity (360.2 mA h g^-1, corresponding to 89.6% of the capacity at 0.2 A g^-1 delivered in 1 min) and negligible capacity decay (30 000 cycles) at a high current density of 20 A g^-1. LC-ACF||LiNi_0.8Co_0.1Mn_0.1O₂ (NCM811) full cells deliver an attractive capacity of 118.4 mA h g^-1 (achieving 62.3% state-of-charge within 1.5 min) and a capacity retention of 90.3% after 3000 cycles at an extremely high rate of 20 C (1 C = 210 mA g^-1). LC-ACF||NCM811 pouch cells with outstanding fast-charging performance were also achieved.