Defect engineering of hollow porous N, S co-doped carbon spheres-derived materials for high-performance hybrid supercapacitors

Defect engineering, such as introducing heteroatoms and vacancies into the electrode materials, provides a feasible strategy for boosting the electrochemical characteristics of hybrid supercapacitors. In this work, hollow N, S co-doped carbon (HNSC) spheres with high specific surface area are fabricated through the carbonizationetching process. Thanks to the unique porous architecture and multiple heteroatoms doping, the obtained HNSC electrode achieves an excellent capacitance of 330.4 F g-1 at 1 A g-1 and superior capacitance retention of 97 % after 10,000 cycles in 6 M KOH. Subsequently, the Co3S4 nanoparticles with controllable sulfur vacancies (VsCo3S4) are homogeneously deposited on the HNSC skeleton by a facile chemical reduction strategy. The fabricated Vs-Co3S4/HNSC cathode exhibits a compelling electrochemical capacity of 497.2 C g-1 at 1 A g-1 and a prominent cycle life of 98.1 % after 10,000 cycles in 6 M KOH. Noticeably, benefiting from the defects regulation and unique structures of HNSC and Vs-Co3S4/HNSC, the constructed hybrid supercapacitor of VS-Co3S4/HNSC// HNSC reaches a marvelous energy density of 71.4 Wh kg- 1 at 925.3 W kg- 1 with only 8.1 % capacity loss within 15,000 cycles at 10 A g-1. Such eminent electrochemical features inspire the rational design of advanced defectmodulated electrode materials for energy storage applications.