In this study,we successfully synthesized aδ-MnO_(2)cathode with O vacancies,encapsulated by C derived from pyromellitic acid,using a facile hydrothermal method followed by annealing in an Ar atmosphere.The cathode’s structural stability and charge transfer kinetics are enhanced by inhibiting the formation of the by-product Zn_(4)SO_(4)(OH)_(6)4H_(2)O,regulating the Mn valence state,and suppressing the Jahn–Teller effect through the synergy of C encapsulation and O vacancies.This results in remarkable electrochemical performance,including a large capacity of 421.2 mAh g^(-1)at 0.1 A g^(-1),a high specific energy density of595.53 Wh kg^(-1),and exceptional long-cycle life stability with 90.88%over 4000 cycles at 10 A g^(-1),together with superior coulombic efficiency(~100%)in pure ZnSO_(4)electrolyte.Moreover,the cathode materials demonstrate specific antitumor efficacy.In brief,this work introduces an in situ syntheticC encapsulatedδ-MnO_(2)with O vacancies expected to be applied in both large-scale energy storage and biomedicine.
