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

[Display omitted] •HNSC spheres with hollow and porous structure were fabricated by defect engineering.•Vs-Co3S4 nanoparticles with controllable sulfur vacancies were deposited on HNSC.•The HNSC and VS-Co3S4/HNSC electrodes deliver admirable electrochemical features.•The VS-Co3S4/HNSC//HNSC device reveals high energy density and superior cycle life. 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 carbonization-etching 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 (Vs-Co3S4) 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 defect-modulated electrode materials for energy storage applications.