Catalytic pyrolysis of lignin for renewable aromatics by lithium-ion battery cathodes and gas-solid/gas discharge refining

This study converted lignin into renewable aromatics by lithium-ion battery cathodes catalysis and plasma refining. The pyrolysis behavior of lignin catalyzed by thermal-treated cathodes was initially evaluated, and then the effects of cathodes (LCO, LMO, LTO, and LFP) and plasma discharge on products were investigated. Cathodes intensified the lignin pyrolysis, and LFP increased the comprehensive characteristic index by 3.36 times. The lignin pyrolysis just yielded 12.45 % of organics, containing 66.51 % of phenols. Catalytic pyrolysis led to varying increases in gas and organic yields, in which LFP elevated organic yield to 19.12 % and monocyclic aromatics occupied 53.06 %. The pyrolysis product reduction and gas-solid discharge synergy caused the collapse of cathodes and the reduction of Co, Mn, and Fe. Especially, LTO and LFP resulted in higher specific surface areas (170.60 m2/g and 154.48 m2/g) and pore volumes (0.171 cm3/g and 0.158 cm3/g) of chars. Gas discharge improved the deoxygenation upgrading and higher current increased the monocyclic aromatic selectivity to 74.13 %. Due to strong gas-solid discharge and plasma sheath transfer at 500 mA, carbonaceous species accumulated outward along the discharge channels, formed the woolen-like flocs structure and increased char textual parameters to 329.38 m2/g and 0.323 cm3/g.