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.