3D printing of carbon tile-modulated well-interconnected hierarchically porous pseudocapacitive electrode

Abstract

Pseudocapacitive electrode architecture with well-interconnected open pores is essential and critical to the high-performance energy storage. However, challenges remain pertaining to consistent and scalable manufacturing, as well as fast ion/electron transport, especially at a high mass loading of active materials. Herein, with kapok-derived proper-curved quasi-2D carbon tile (CT) featuring thin wall and high microporosity as unique skeleton support, a novel pseudocapacitive CT-single-wall carbon nanotube (SWNT)-NiCo2O4 electrode was constructed via a scalable and controllable extrusion-based 3D printing strategy. The resulting 3D-printed electrode demonstrated abundant well-interconnected hierarchical pores and continuous conductive network built by coupling CTs and SWNTs, thereby enabling uniform and high mass loading of active NiCo2O4 (31 mg cm−2), and meanwhile guaranteeing unimpeded channels and adequate pathways acting as “superhighways” for ultrafast ion diffusion and electron transport throughout the entire device. Benefiting from these prominent features, an asymmetric supercapacitor assembled with 3D-printed CT-modulated electrode delivered high specific capacitance (588 mF cm−2) and energy density (138 µWh cm−2), exceptional long-term cycling stability (82% after 50000 cycles), and superior capacity even at large electrode thickness. This work has shed light on new strategies for fabricating rational pseudocapacitive electrode architectures toward high-capacity, rapidly cycling devices.