Sustainable Lignin‐Derived Carbon as Capacity‐Kinetics Matched Cathode and Anode towards 4.5 V High‐Performance Lithium‐Ion Capacitors

Abstract

The Li‐ion capacitors (LICs) develop rapidly due to their double‐high features of high‐energy density and high‐power density. However, the relative low capacity of cathode and sluggish kinetics of anode seriously impede the development of LICs. Herein, the precisely pore‐engineered and heteroatom‐tailored defective hierarchical porous carbons (DHPCs) as large‐capacity cathode and high‐rate anode to construct high‐performance dual‐carbon LICs have been developed. The DHPCs are prepared based on triple‐activation mechanisms by direct pyrolysis of sustainable lignin with urea to generate the interconnected hierarchical porous structure and plentiful heteroatom‐induced defects. Benefiting from these advanced merits, DHPCs show the well‐matched high capacity and fast kinetics of both cathode and anode, exhibiting large capacities, superior rate capability and long‐term lifespan. Both experimental and computational results demonstrate the strong synergistic effect of pore and dopants for Li storage. Consequently, the assembled dual‐carbon LIC exhibits high voltage of 4.5 V, high‐energy density of 208 Wh kg−1, ultrahigh power density of 53.4 kW kg−1 and almost zero‐decrement cycling lifetime. Impressively, the full device with high mass loading of 9.4 mg cm−2 on cathode still outputs high‐energy density of 187 Wh kg−1, demonstrative of their potential as electrode materials for high‐performance electrochemical devices.