(Invited) Rational Interfacial Design for Advanced Batteries

Lithium (Li) metal batteries have attracted world-wide attention due to its low density (0.534 g/cm3), high theoretical capacity (3,860 mAh/g), and low electrochemical potential (-3.04 V vs. SHE), enabling their potential to double the cell-level energy of the state-of-the-art lithium-ion batteries. However, there are still key materials issues that inhibit lithium metal and high-voltage cathodes from being commercialized as the anode and cathode, respectively, for rechargeable battery applications. For Li metal anode, the chemical and morphological (e.g., grain distribution, surface roughness, etc.) non-uniformity, coupled with the high reactivity of lithium drive heterogeneous solid-electrolyte interphase (SEI) formation, poor ionic flux distribution, active material consumption, and rapid dendrite growth. Currently, there are ex-situ and in-situ approaches to address the above issues. For example, one of approaches is to coat artificial SEI layers on Li metal anode surfaces. The component, distribution and structures of SEI layers should be designed and well controlled. The other approach is to exploit advanced electrolyte to in-situ form high-performance SEI layers. At the cathode side, due to instable cathode structure, oxygen evolution and side reaction between electrolyte and cathode materials at high voltage (> 4.3V vs. Li/Li+), the robust and Li ion conductive cathode electrolyte interphase (CEI) layers are required to stabilize the cathode at high voltage. In this talk, we will present our recent work from the three aspects: a) novel closed-host bi-layer porous/dense artificial SEI layers were designed[1]; b) the microstructures of localized high-concentration electrolyte were deeply understood and thus new electrolytes with high-performance SEI layers being formed were discovered;[2] (c) a novel artificial CEI coating was proposed to stabilize the cathode at the high voltage. References: [1] Efaw, Corey M., et al. "A closed-host bi-layer dense/porous solid electrolyte interphase for enhanced lithium-metal anode stability." Materials Today 49 (2021): 48-58. [2] Efaw, Corey M., et al. "Localized High-Concentration Electrolytes Get More Localized Through Micelle-Like Structures." Nature Materials, 2023