Quasi-solid-state thermogalvanic cells (QTCs) with gel electrolytes are attractive for wearable heat harvesting because they prevent leakage and retain flexibility. However, their power output is limited by slow ion diffusion in gels and insufficient interfacial reaction activity. Here, we report an all-flexible, high-performance QTC enabled by nickel-electroplated textile electrodes and cesium-based structure-breaking salts in gel electrolytes. The nickel textiles offer an enhanced active surface area through oxidation, forming oxygen vacancies that accelerate redox reactions. Meanwhile, cesium salts disrupt the hydrogen-bonded network in gel electrolytes, improving ion transport and redox kinetics. This synergistic design markedly enhances effective cell conductivity and power density without noble-metal electrodes, achieving record-high values for the reported QTCs and enabling the operation of small electronics using body heat.