An Ag2V4O11 (SVO) cathode material prepared by microwave (MW)-assisted solid-state synthesis (MW-SVO) was developed for lithium primary batteries for implantable cardioverter/defibrillators (ICDs). This paper presents the results of physical–chemical and electrochemical characterizations of MW-SVO as well as those of SVO prepared by conventional thermal route (T-SVO). A specific effect of MWs which accelerates the synthesis reaction and contributes to yield a material of different morphology and degree of crystallinity compared with those of T-SVO was observed. The results of pulsed electrochemical tests carried out at 37°C in operative conditions of ICDs on Li/MW-SVO batteries with cathode mass loading sized for practical use are also reported. These tests demonstrated that MW-SVO can be used for high performing lithium primary battery delivering in few seconds the specific energy values required by ICD application.