Triboelectric nanogenerators (TENGs) have been extensively studied in recent years due to their potential for energy harvesting and self-powered sensing. However, most of the research has focused on only exploring new materials, while there has been limited examination of how optimizing material properties or device system designs could enhance TENG devices. To address this gap, this research presents a pioneering approach using thermally reactivated electrode materials derived from waste alkaline batteries (WABs) for future energy harvesting applications in TENGs. By systematically investigating how the oxygen content and surface morphology affect TENG device performance at different pyrolysis temperatures, we achieved optimal TENG material at 500 °C, exhibiting outstanding output voltage, current, and power density of 790   V, 40.27   µA, and 529.375   µW/cm2, respectively. Mechanical stability testing revealed that the TENG device based on RC-WABs remains stable for over 40,000 cycles with consistent output performance. Furthermore, the proposed method employs a simple and efficient pyrolysis technique to reactivate the cathode and anode materials of WABs, operating at low temperatures without activating gases or inert atmospheres. To validate real-time applicability, the TENG device was successfully employed to power various applications, such as illuminating 150 LEDs and operating a digital calculator. This research provides a new perspective on the use of waste materials for energy harvesting applications and offers a potential solution for recycling waste alkaline batteries, which is one of the significant environmental problems. Overall, the findings highlight the potential of the proposed approach for future TENG device design and provide a new direction for sustainable energy harvesting.