Conductive additive (carbonaceous materials) - Induced changes in electrochemical properties of lanthanum phosphate for energy storage devices

A conductive additive is a crucial component of the electrode, along with an active material and binder, in electrochemical energy storage technologies. Therefore, the electrochemical behavior of lanthanum phosphate (LaPO₄) was investigated by preparing electrodes with different conductive additives. FTIR and Raman analyses revealed characteristic La–O and PO₄³⁻ vibrational modes, while UV–Vis and photoluminescence (PL) studies indicated a direct optical bandgap of 2.17 eV and strong emission at 379 nm, respectively, signifying high optical quality. XRD and EDX analysis confirm the effective preparation of LaPO₄ with an average crystallite size of 41.5 nm. The three electrodes were prepared using LaPO₄ as an active material with different additives (graphite, activated carbon, and carbon black). The different types of carbon additives predominantly affect the charge storage behavior of the primary redox-active material. The electrochemical response exhibited that the LaPO₄-II (activated carbon) electrode outperformed the other two electrodes. LaPO₄-II exhibited hybrid-type behavior, whereas a battery-grade behavior was witnessed in the graphite and carbon black - based electrodes. The highest specific capacity of 733 Cg^-1 for LaPO₄-II was observed at 5 mVs⁻¹. The prototype device based on LaPO₄-II//AC exhibited a specific capacity of 301 Cg^-1 at a current density of 1 Ag^-1, with maximum energy and power densities of 13.5 Wh·kg⁻¹and 2450 W kg⁻¹, respectively. This studies established a new pathways for selecting the carbon additives for enhancing the electrochemical performance of energy storage devices.