LAUSR

Enhancing both mechanical and electrochemical properties of direct‐spun carbon nanotube fiber (CNTF) is essential for energy harvesting applications, but conventional strategies often improve one at the expense of the other. Herein, a sucrose‐derived porous carbon network is internally formed within the inter‐bundle voids of direct‐spun CNTFs, simultaneously enhancing their mechanical and electrochemical properties. This sucrose‐derived porous internally embedded carbon (SPINE‐C) reinforced inter‐bundle connectivity while preserving the alignment of CNTs, thereby enhancing the tensile strength (235–350 MPa), torsional durability (177.5–294.4 mN·m·mm −3 ), and toughness (5–20 J g −1 ) of the CNTFs without compromising their flexibility. Additionally, the microporous structure of SPINE‐C expanded the electrochemically accessible surface area, improving in charge storage capacity from 7.2 to 8.0 F g −1 . These enhancements in mechanical and electrochemical properties translated into superior energy harvesting performance in SPINE‐C‐based mechano‐electrochemical energy harvester (MEEH), with the power density increasing from 16.2 to 46.0 W kg −1 at 1 Hz—a 2.8‐fold enhancement. These results highlight the potential of the SPINE‐C strategy as a scalable and high‐performance electrode platform for fiber‐based energy harvesters, wearable electronics, and smart textiles.