High-Performance Lithium-Ion Capacitors Produced by\nAtom-Thick Carbon Cathode and Nitrogen-Doped Porous Carbon Anode

Abstract

The all-carbon lithium-ion capacitor\n(LIC) has the advantage of\nfast ion and electron transmission and is the most promising electrochemical\nenergy storage equipment. Here, we reported a high-performance hybrid\nall-carbon LIC using an atom-thick carbocoal-derived hierarchical\nporous carbon (CHPC) cathode and a nitrogen-doped porous carbon (NPC)\nanode. CHPC and NPC were readily prepared through in situ catalytic\nactivation and pyrolysis of low-cost anthracite and asphalt powder,\nrespectively. The CHPC endows a large BET specific surfaces area of\n3160 m² g^–1, a continuous highly curved\nthree-dimensional (3D) network of atomic thickness, and wide pores\nof 0.95–3.68 nm, which give the CHPC with excellent capacitive\nmerits. Meanwhile, the NPC possesses lots of active adsorption sites\nand expanded interlamellar space for effective storage and migration\nof Li⁺, endowing the rapid kinetics. Hybrid LICs by coupling\nsuch CHPC cathode and pre-lithiation NPC anode yielded high gravimetric\ncapacitance (139 mAh g^–1_cathode at 0.5\nA g^–1) and energy density (220 Wh kg_total^–1 at a specific power of 805 W kg^–1) in organic electrolyte. Furthermore, the process of obtaining atom-thick-wall\nhigh-surface-area carbon at low cost is readily scalable.