Toward the Integration of a Silicon/Graphite Anode-Based Lithium-Ion Battery in Photovoltaic Charging Battery Systems

Solar photovoltaic (PV) energy generation is highly dependent on weather conditions and only applicable when the sun is shining during the daytime, leading to a mismatch between demand and supply. Merging PVs with battery storage is the straightforward route to counteract the intermittent nature of solar generation. Capacity (or energy density), overall efficiency, and stability at elevated temperatures are among key battery performance metrics for an integrated PV-battery system. The performance of high-capacity silicon (Si)/graphite (Gr) anode and LiNi_0.6Mn_0.2Co_0.2O₂ (NMC622) cathode cells at room temperature, 45, and 60 °C working temperatures for PV modules are explored. The electrochemical performance of both half and full cells are tested using a specially formulated electrolyte, 1 M LiPF₆ in ethylene carbonate: diethyl carbonate, with 5 wt % fluoroethylene carbonate, 2 wt % vinylene carbonate, and 1 wt % (2-cyanoethyl)triethoxysilane. To demonstrate solar charging, perovskite solar cells (PSCs) are coupled to the developed batteries, following the evaluation of each device. An overall efficiency of 8.74% under standard PV test conditions is obtained for the PSC charged lithium-ion battery via the direct-current-direct-current converter, showing the promising applicability of silicon/graphite-based anodes in the PV-battery integrated system.