• A self-assembled flexible Ti3C2Tx MXene-based thermally chargeable supercapacitor (TCSC) was successfully fabricated using Ti3C2Tx MXene as the electrode and NaClO4/PEO gel as the electrolyte.
• The TCSC device exhibits an excellent average Seebeck coefficient of 11.8 mV·K−1, enabling efficient thermal-to-electrical energy conversion.
• The device demonstrates good cycling stability under various temperature differences, indicating reliable performance for practical applications.
• Multiple practical demonstrations confirm that Ti3C2Tx MXene-based TCSCs are promising candidates for self-powered integrated electronic devices.