Enhanced Capacity Retention of Li3V2(PO4)3-Cathode-Based Lithium Metal Battery Using SiO2-Scaffold-Confined Ionic Liquid as Hybrid Solid-State Electrolyte

• Published in: Molecules (Basel, Switzerland) Vol. 28; no. 13; p. 4896
• Main Authors: Peng, Shihao, Luo, Jiakun, Liu, Wenwen, He, Xiaolong, Xie, Fang
• Format: Journal Article
• Language: English
• Published: Basel MDPI AG 21.06.2023; MDPI
• Subjects: Adsorption; Cathodes; cycling performance; Electrochemistry; Electrode materials; Electrolytes; Energy; High voltage; Ion currents; Ionic liquids; Ions; Li3V2(PO4)3; Lithium; Lithium batteries; lithium metal battery; Metals; Morphology; Nanoparticles; Nitrogen; Scaffolds; Scanning electron microscopy; Side reactions; Silicon dioxide; Solid state; solid-state electrolyte; Spectrum analysis; Voltage
• ISSN: 1420-3049; 1420-3049
• DOI: 10.3390/molecules28134896

Li3V2(PO4)3 (LVP) is one of the candidates for high-energy-density cathode materials matching lithium metal batteries due to its high operating voltage and theoretical capacity. However, the inevitable side reactions of LVP with a traditional liquid-state electrolyte under high voltage, as well as the uncontrollable growth of lithium dendrites, worsen the cycling performance. Herein, a hybrid solid-state electrolyte is prepared by the confinement of a lithium-containing ionic liquid with a mesoporous SiO2 scaffold, and used for a LVP-cathode-based lithium metal battery. The solid-state electrolyte not only exhibits a high ionic conductivity of 3.14 × 10−4 S cm−1 at 30 °C and a wide electrochemical window of about 5 V, but also has good compatibility with the LVP cathode material. Moreover, the cell paired with a solid-state electrolyte exhibits good reversibility and can realize a stable operation at a voltage of up to 4.8 V, and the discharge capacity is well-maintained after 100 cycles, which demonstrates excellent capacity retention. As a contrast, the cell paired with a conventional liquid-state electrolyte shows only an 87.6% discharge capacity retention after 100 cycles. In addition, the effectiveness of a hybrid solid-state electrolyte in suppressing dendritic lithium is demonstrated. The work presents a possible choice for the use of a hybrid solid-state electrolyte compatible with high-performance cathode materials in lithium metal batteries.