RESUMO
Herein, we report halide nanocomposite solid electrolytes (HNSEs) that integrate diverse oxides with alterations that allow tuning of their ionic conductivity, (electro)chemical stability, and specific density. A two-step mechanochemical process enabled the synthesis of multimetal (or nonmetal) HNSEs, MO2-2Li2ZrCl6, as verified by pair distribution function and X-ray diffraction analyses. The multimetal (or nonmetal) HNSE strategy increases the ionic conductivity of Li2ZrCl6 from 0.40 to 0.82 mS cm-1. Additionally, cyclic voltammetry test findings corroborated the enhanced passivating properties of the HNSEs. Notably, incorporating SiO2 into HNSEs leads to a substantial reduction in the specific density of HNSEs, demonstrating their strong potential for achieving a high energy density and lowering costs. Fluorinated SiO2-2Li2ZrCl5F HNSEs exhibited enhanced interfacial compatibility with Li6PS5Cl and LiCoO2 electrodes. Cells employing SiO2-2Li2ZrCl5F with LiCoO2 exhibit superior electrochemical performance delivering the initial discharge capacity of 162 mA h g-1 with 93.7% capacity retention at the 100th cycle at 60 °C.
RESUMO
Designing highly conductive and (electro)chemical stable inorganic solid electrolytes using cost-effective materials is crucial for developing all-solid-state batteries. Here, we report halide nanocomposite solid electrolytes (HNSEs) ZrO2(-ACl)-A2ZrCl6 (A = Li or Na) that demonstrate improved ionic conductivities at 30 °C, from 0.40 to 1.3 mS cm-1 and from 0.011 to 0.11 mS cm-1 for Li+ and Na+, respectively, compared to A2ZrCl6, and improved compatibility with sulfide solid electrolytes. The mechanochemical method employing Li2O for the HNSEs synthesis enables the formation of nanostructured networks that promote interfacial superionic conduction. Via density functional theory calculations combined with synchrotron X-ray and 6Li nuclear magnetic resonance measurements and analyses, we demonstrate that interfacial oxygen-substituted compounds are responsible for the boosted interfacial conduction mechanism. Compared to state-of-the-art Li2ZrCl6, the fluorinated ZrO2-2Li2ZrCl5F HNSE shows improved high-voltage stability and interfacial compatibility with Li6PS5Cl and layered lithium transition metal oxide-based positive electrodes without detrimentally affecting Li+ conductivity. We also report the assembly and testing of a Li-In||LiNi0.88Co0.11Mn0.01O2 all-solid-state lab-scale cell operating at 30 °C and 70 MPa and capable of delivering a specific discharge of 115 mAh g-1 after almost 2000 cycles at 400 mA g-1.