Advanced sodium-ion battery anode material prepared by regulating an environmentally friendly hard carbon precursor through bio-based molecular coupling

A bio-based phenolic resin precursor fully replacing toxic phenol and formaldehyde delivers hard carbon anode with 356.2 mAh g −1 , 84.2% ICE and 90.5% retention over 1000 cycles at 2000 mA g −1 , and a full cell with O3 cathode achieves 241 Wh kg −1 .