Modulating Electronic Structure with Linearly Fused Pyrazine Units for High-Voltage and Stable Zinc-Organic Batteries CathodeOA

High-voltage n-type organic cathode materials are critical for constructing zinc-organic batteries(ZOBs)with high en-ergy density and long cycle life.However,the intrinsically unfavorable electronic structures and relatively high LUMO energy levels of most n-type materials often lead to sluggish kinetics,high solubility,and suboptimal discharge voltages(<0.8 V).Here,we design a small molecule,quinoxalino[2’,3’:5,6]pyrazino[2,3-f][1,10]phenanthroline(DPQP),as a ZOB cathode by introducing locally electron-deficient motifs into the conjugated backbone of aromatic compounds.The linear-ly fused pyrazine units extending the pyrazine-benzene framework effectively optimize the electronic structure,thereby significantly enhancing the discharge voltage.Meanwhile,the expandedπ-conjugated plane suppresses dissolution and accelerates charge-transfer kinetics.Benefiting from these features,the DPQP electrode exhibits an exceptional increase in average operating voltage from 0.61 V to 1.07 V(vs.Zn²+/Zn)at 0.1 A·g^(-1),with an overpotential of only 140 mV.Notably,no discernible voltage decay occurs as the current density increases,indicating rapid and highly reversible redox kinetics.Furthermore,the DPQP cathode delivers outstanding cycling stability,maintaining over 2000 h of continuous operation at 0.1 A·g^(-1)and retaining 82.5%of its capacity after more than 10,000 cycles at 10 A·g^(-1).Remarkably,the DPQP electrode also demonstrates excellent tolerance to extreme temperatures,achieving stable electrochemical performance across a wide temperature range from-20°C to 60°C.In addition,a series of spectroscopic and microscopic characterizations confirm the highly reversible redox behavior and Zn²+storage mechanism of the DPQP cathode.