Carbon materials are proving to hold the key to substantial advances in today’s energy storage technologies. Naturally abundant biomass, such as cotton and wheat flour, and even currently wasted resources, such as banana peels and recycled papers, have been successfully converted to produce renewable carbon materials for energy storage systems via a low-cost and high throughput manufacturing process. Excitingly, these biomass-derived renewable activated carbon scaffolds usually possess hierarchically porous structures which are beyond the synthetic materials, making them ideal backbones for depositing active materials with higher capacity for supercapacitors, and for hosting sulfur in lithium-sulfur batteries to manipulate the “shuttle effects” of polysulfides. Specifically, biomass-derived activated cotton textile (ACT) has been demonstrated an excellent flexible conductive substrate to fabricate flexible power sources, such as flexible supercapacitors with enhanced capacity and flexible lithium-sulfur (Li-S) batteries with prolonged lifespan. When the with magnetic Fe/Fe3C nanoparticles embedded ACT was used as a sulfur host, an obviously increased lifespan of the assembled Li-S cell can be ascribed to a new proposed magnetic field-assisted polysulfides trapping mechanism. Besides flexible ACT, carbon nanotubes (CNTs) have also successfully derived from the natural yeast-fermented wheat dough without using any extra-catalysts or additional carbon sources. Yeast-derived carbon nanotubes from the fermented wheat dough not only provide an ideal sulfur host for Li-S batteries with a record lifespan of 5000 cycles but also expand our current understanding of the synthesis of carbon nanotubes. Using biomasses is definitely the right track towards making renewable carbon materials for future energy storage devices.