Contribution of Acetylene Black on Electrochemical Performance of Vanadium Hydride Anodes for All-Solid-State Lithium Ion Battery

The development of high-capacity and safe anode materials remains a major challenge for all-solid-state lithium-ion batteries. Metal hydrides have emerged as promising candidates due to their high theoretical capacity and low operating potential; however, their poor electronic conductivity often limits performance. In this study, we systematically investigated vanadium lithium hydride (V-LiH) composite anodes containing different amounts of acetylene black (AB) and LiBH₄ as the solid electrolyte. Galvanostatic electrochemical cycling and galvanostatic intermittent titration technique (GITT) were performed to evaluate the influence of conductive carbon content on the voltage profile, polarization, and reaction stability. Cells with less than 20 wt.% AB showed no activity, while those with higher AB fractions exhibited distinct conversion plateaus. The mid-AB range (30-40 wt.%) displayed the flattest and most stable plateaus, indicating optimal electronic percolation and interface formation. After separating the AB contribution, a nonlinear increase in normalized conversion capacity was observed with increasing AB content. These findings elucidate the role of conductive carbon in reducing overpotential and stabilizing the V-LiH conversion reaction, providing insight for the design of high-performance hydride-based anodes for all-solid-state lithium-ion batteries.