Abstract: To enhance the performance of betavoltaic batteries, we investigated the effects of depletion region width, diffusion length, and electrode structure on output power. By optimizing the design and improving the fabrication processes of radioisotope source thickness, converter structure, and electrodes, we successfully developed a tritiated titanium-SiC-based betavoltaic battery with the form of integrated radioisotope source and converter. Compared to the test results using a discrete tritiated titanium and a converter, the integrated approach of tritiated titanium and the converter significantly improved the output performance of the betavoltaic battery, achieving a maximum output power of 21.4 nW. This performance is among the highest reported for similar betavoltaic batteries. This work provides a valuable reference for developing high-performance betavoltaic batteries.