Cathode and electrolyte materials are key components of Li-ion batteries, which influence the safety and electrochemical characteristics. This study focuses on the development and characterization of glassy and glass–ceramic showing either ionic or mixed ionic-electronic conductivity, that can be used as electrolytes or cathodes, respectively, in energy storage devices. Homogenous glasses within the (30 + x)Li2WO4–(70-x)(45.5Li2O–54.5P2O5) system are produced using the melt quenching technique. Structural characterization via XRD and IR spectroscopy revealed diverse structural units. UV–visible absorption studies evaluated optical properties, while impedance spectroscopy measured electrical conductivity. Li2WO4 addition increased density, molar volume, and microhardness. Enhanced electrical conductivity was observed, notably reaching 3.22 × 10−6 (Ω−1 cm−1) at room temperature and 3.13 × 10−5 (Ω−1 cm−1) at 423 K. The richer Li2WO4 materials exhibited ionic conductivity associated to lower activation energy around 0.20 eV. Conductivity’s frequency dependency analysis suggested a correlated barrier hopping mechanism.