Biomass-Derived Electrode for Next Generation Lithium-Ion Capacitors

We report the fabrication of a carbon‐based high energy density Li‐ion hybrid electrochemical capacitor (Li‐HEC) from low cost and eco‐friendly materials. High surface area (2448±20 m2 g−1) activated carbon (AC) is derived from the environmentally threatening plant, Prosopis juliflora, and used as the positive electrode in a Li‐HEC assembly. Natural graphite is employed as negative electrode and electrochemically pre‐lithiated prior to the Li‐HEC fabrication. The Li‐HEC delivers a specific energy of 162.3 Wh kg−1 and exhibits excellent cyclability (i.e., ∼79 % of initial capacity is retained after 7000 cycles). The superior electrochemical performance of Li‐HEC benefits from the tube‐like unique structural features of the AC. Also, the presence of a graphitic nanocarbon network improves the ion transport, and the formed micro‐ and meso‐porous network acts as reservoir for the accommodation of charge carriers. Plant‐based capacitors: Carbon‐based high energy density Li‐ion hybrid electrochemical capacitors (Li‐HEC) are fabricated using carbons derived from an environmentally threatening plant. Superior electrochemical performance is achieved owing to the tube‐like unique structural features of the derived activated carbon material and the presence of a graphitic nanocarbon network, which improves the ion transport and acts as reservoir for the accommodation of charge carriers.