In response to the urgent need for sustainable and environmentally friendly materials, this study focuses on enhancing the flame retardancy and mechanical properties of epoxy composites using eco-friendly, non-halogen flame-retardant hybrid fillers. These fillers are synthesized from tannic acid (TA) and upcycled carbon black derived from waste tires (WT-CB) via a mechano-fusion process. The resulting TA/WT-CB fillers exhibit a core–shell structure, with WT-CB uniformly coating the TA surface, significantly improving flame retardancy compared to TA alone. When incorporated into epoxy resin, the TA/WT-CB fillers not only enhance flame resistance but also improve the composite’s mechanical properties. Optimal performance was observed at a filler content of 5 wt.%, where the composite demonstrated superior flame retardancy and mechanical strength. This innovative approach not only addresses fire safety concerns but also promotes sustainability by utilizing upcycled waste materials, offering a promising solution for environmentally conscious flame-retardant technologies.

This study prepares highly porous carbon (c-fPI) for lithium-ion battery anode that starts from the synthesis of fluorinated polyimide (fPI) via a step polymerization, followed by carbonization. During the carbonization of fPI, the decomposition of fPI releases gases which are particularly from fluorine-containing moiety (–CF3) of fPI, creating well-defined microporous structure with small graphitic regions and a high specific surface area of 934.35 m2 g− 1. In particular, the graphitic region of c-fPI enables lithiation–delithiation processes and the high surface area can accommodate charges at electrolyte/electrode interface during charge–discharge, both of which contribute electrochemical performances. As a result, c-fPI shows high specific capacity of 248 mAh g− 1 at 25 mA g− 1, good rate-retention performance, and considerable cycle stability for at least 300 charge–discharge cycles. The concept of using a polymeric precursor (fPI), capable of forming considerable pores during carbonization is suitable for the use in various applications, particularly in energy storage systems, advancing materials science and energy technologies.