Konjac glucomannan (KGM) featuring abundant oxygen functional groups has been elaborately designed to enhance Zn reversibility. Importantly, -OH and C[double bond, length as m-dash]O groups as active sites could redistribute the Zn2+ concentration field and modulate the plating/stripping rate, further enabling uniform Zn deposition without dendrite growth. The Zn@KGM anode enables an advanced Zn-ion supercapacitor to deliver an impressive rate performance and cycling stability (up to 5000 cycles accompanied by a coulombic efficiency of 99.8%).