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The changes introduced by both ball milling and the addition of small amounts of TiF<inline-formula><math display="inline"><semantics><msub><mrow></mrow><mn>3</mn></msub></semantics></math></inline-formula> in the kinetics of the hydrogen desorption of three different Ca(BH<inline-formula><math display="inline"><semantics><msub><mrow></mrow><mn>4</mn></msub></semantics></math></inline-formula>)<inline-formula><math display="inline"><semantics><msub><mrow></mrow><mn>2</mn></msub></semantics></math></inline-formula> polymorphs (<inline-formula><math display="inline"><semantics><mi>α</mi></semantics></math></inline-formula>, <inline-formula><math display="inline"><semantics><mi>β</mi></semantics></math></inline-formula> and <inline-formula><math display="inline"><semantics><mi>γ</mi></semantics></math></inline-formula>) have been systematically investigated. The samples with different polymorphic contents, before and after the addition of TiF<inline-formula><math display="inline"><semantics><msub><mrow></mrow><mn>3</mn></msub></semantics></math></inline-formula>, were characterized by powder X-ray diffraction and vibrational spectroscopy. The hydrogen desorption reaction pathways were monitored by differential scanning calorimetry. The hydrogen desorption of Ca(BH<inline-formula><math display="inline"><semantics><msub><mrow></mrow><mn>4</mn></msub></semantics></math></inline-formula>)<inline-formula><math display="inline"><semantics><msub><mrow></mrow><mn>2</mn></msub></semantics></math></inline-formula> depends strongly on the amount of coexistent <inline-formula><math display="inline"><semantics><mi>α</mi></semantics></math></inline-formula>, <inline-formula><math display="inline"><semantics><mi>β</mi></semantics></math></inline-formula> and <inline-formula><math display="inline"><semantics><mi>γ</mi></semantics></math></inline-formula> polymorphs as well as additional ball milling and added TiF<inline-formula><math display="inline"><semantics><msub><mrow></mrow><mn>3</mn></msub></semantics></math></inline-formula> to the sample. The addition of TiF<inline-formula><math display="inline"><semantics><msub><mrow></mrow><mn>3</mn></msub></semantics></math></inline-formula> increased the hydrogen desorption rate without significant dissociation of the fluoride. The combination of an <inline-formula><math display="inline"><semantics><mi>α</mi></semantics></math></inline-formula>-Ca(BH<inline-formula><math display="inline"><semantics><msub><mrow></mrow><mn>4</mn></msub></semantics></math></inline-formula>)<inline-formula><math display="inline"><semantics><msub><mrow></mrow><mn>2</mn></msub></semantics></math></inline-formula> rich sample with 10 mol% of TiF<inline-formula><math display="inline"><semantics><msub><mrow></mrow><mn>3</mn></msub></semantics></math></inline-formula> and 8 h of milling led to up to 27 <inline-formula><math display="inline"><semantics><mrow><msup><mrow></mrow><mo>°</mo></msup><mi mathvariant="normal">C</mi></mrow></semantics></math></inline-formula> decrease of the hydrogen desorption peak temperature.