Scalable synthesis of pitch‐derived soft carbon with graphitic nanodomains embedded in amorphous matrix for high‐energy pouch‐type lithium‐ion capacitors

Abstract Promising energy storage devices, lithium‐ion capacitors (LICs), integrate the high energy density characteristic of lithium‐ion batteries with the superior power density found in supercapacitors. A key challenge impeding their practical deployment, however, is the kinetic disparity between the cathode’s rapid charge acceptance and the anode’s sluggish reaction rates. Herein, we present a cost‐effective strategy to address this limitation through the rational design of pitch‐derived soft carbon anodes. By precisely controlling the carbonization process of pitch, the pitch‐based soft carbon material (PC800) synthesized at a carbonization temperature of 800 °C exhibits a unique hybrid structure consisting of an amorphous carbon matrix embedded with graphitic nanodomains. This hierarchical structure not only provides abundant active sites and efficient ion diffusion pathways, but also ensures rapid electron transport, thereby enabling excellent rate capability. The PC800 electrode delivers a remarkable reversible capacity of 319.2 mAh g −1 at 0.1 A g −1 and maintains 131.6 mAh g −1 even at 5 A g −1 . When assembled into a full‐cell LIC with activated carbon cathode, the device achieves a high energy density of 159.4 Wh kg −1 at 246.7 W kg −1 and retains 42.8 Wh kg −1 under a high power density of 11 kW kg −1 (based on the total mass of active materials). Notably, the scaled‐up production of PC800 demonstrates excellent structural stability and electrochemical consistency in pouch‐type LICs, achieving an energy density of 30 Wh kg −1 based on the overall device mass. This work highlights the feasibility of transforming low‐cost pitch precursors into high‐performance carbon anodes through structural engineering, thereby enabling the industrial development of advanced LICs with balanced energy and power characteristics.