A novel flower-like architecture comprised of 3D interconnected Co–Al-Ox/Sy decorated lignosulfonate-derived carbon nanosheets for flexible supercapacitors and electrocatalytic water splitting

It is a great challenge to construct low-cost nanostructured carbon as supports of transition metal oxides/chalcogenides for electrochemical energy storage and conversion applications. Herein, a facile and sustainable strategy is demonstrated that biomass-derived lignosulfonate (LS) as carbon precursors is first co-precipitated with metal salt precursors to form LS-conformal Co–Al layered double hydroxides (Co–Al LDHs) flower-like architectures. After calcination, the pyrolyzates of Co–Al LDHs (Co–Al-Ox) and the corresponding vulcanized products cobalt chalcogenides (Co3S4) are in-situ co-doped into LS-derived carbon nanosheets (LSCN), forming novel flower-like Co–Al-Ox/Sy@LSCN hybrid materials. Owing to the structural and compositional benefits, the resulting hybrid materials and LSCN as electrode materials endowed flexible all-LS based asymmetric supercapacitor high energy density (21.83 Wh Kg−1@374.28 W kg−1). Due to the in-situ multi-component doping and heterojunctions, the hybrid materials could serve as efficient bifunctional electrocatalysts for oxygen evolution reaction (264 [email protected] mA cm−2) and hydrogen evolution reaction (291 [email protected] mA cm−2) and exhibited remarkable stability for overall water splitting (over 100 h). This study not only demonstrates a feasible route to explore low-cost and renewable bio-based electroactive materials for future wearable energy electronics and large-scale hydrogen production, but also proposes a grand opportunity for the valorization of waste LS to high-valued multifunctional materials.