Heterostructure-anchored 3D CNT-bridged graphene architecture via layer-by-layer structural engineering for thick electrodes of supercapacitors

A MnO-Mn3O4/MnS heterostructure-anchored 3D porous graphene architecture with CNT-reinforced interface was successfully constructed and applied as supercapacitors thick electrodes via straightforward layer-by-layer structural engineering. Based on the electrodes, symmetrical supercapacitor with a broadened potential window of 1.3 V obtained a prominent electrochemical performance. [Display omitted] •Thick electrode is constructed by all-laser layer-by-layer structural engineering.•Heterostructure and graphene are synchronously synthesized during laser irradiation.•MnO-Mn3O4/MnS heterostructure provides a high electrochemical activity.•CNT interface and porous graphene supply fast electron/ion transport capability.•The assembled supercapacitor exhibits a prominent electrochemical performance. The emerging thick electrode concept is dedicated to maximize active material areal loading at the device-scale through straightforward structural designs to meet the high energy density demand. Nevertheless, overcoming the sluggish charge kinetics and complex manufacturing route in thick composite electrodes is still challenging. Herein, a novel all-laser structural engineering protocol is developed to construct MnO-Mn3O4/MnS heterostructure-anchored 3D porous graphene architecture with reinforced carbon nanotube (CNT) interface (MHGC) by layer-by-layer laser induction of polyethersulfone film containing manganese acetate precursors without introducing any templates or catalysts. Creatively, along with the synchronous generation of porous graphene and multivalent manganese compounds heterostructures, a uniform distribution process of nanoparticles is integrated into a one-step in-situ laser irradiation, which is unique and straightforward for preparing thick composite electrodes. Besides, the interlayer bridging of CNT network between MnO-Mn3O4/MnS/graphene layers accelerates electron transport, accompanied by the ameliorative deep diffusion of ions by open graphene macropores derived from laser-assisted vaporization. Thanks to the configuration of efficient electronic bridge and ion channel, combined with multi-heterointerface and fast surface reaction kinetics endowed by heterostructure nanoparticles, MHGC electrode with a thickness of 442 μm delivers a high specific capacitance of 954.5 mF cm−2 (at 0.5 mA cm−2). The assembled symmetrical supercapacitor with LiCl aqueous electrolyte exhibits a broadened potential window of 1.3 V, obtaining a prominent energy density