The development of large surface-area and high conductivity electrode is a prerequisite for the construction of high-performance microbial fuel cells. Herein, we report an innovative approach to the fabrication of such high-performance electrodes via the welding assembly of 3D interconnected carbon nanotubes (CNTs) on a carbon-fiber (CF) paper electrode. The minimized interfacial ohmic loss between CNTs and the CF scaffold endowed the microbial fuel cells with the welding-assembled CNT-CF electrodes excellent electrochemical properties with the maximum power density of 2015.6 mW m(-2), 10.0 times higher than that obtained with the untreated CP/CNT (499.8 mW m(-2)) carbon paper anode. As compared to the conventional chemical vapor deposition (CVD) growth technique for fabricating CNT-CF electrodes, this welding assembly approach is more versatile and much easier for up-scaling; on this basis, our work may pave a new avenue to the large-scale production of high-performance microbial fuel cells. (C) 2019 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.