LiPF₆ Induces Phosphorization of Garnet‐Type Solid‐State Electrolyte for Stable Lithium Metal Batteries

Abstract

Garnet solid electrolyte Li6.4La3Zr1.4Ta0.6O12 (LLZTO) is an excellent inorganic ceramic‐type solid electrolyte; however, the presence of Li2CO3 impurities on its surface hinders Li‐ion transport and increases the interface impedance. In contrast to traditional methods of mechanical polishing, acid corrosion, and high‐temperature reduction for removing Li2CO3, herein, a straightforward “waste‐to‐treasure” strategy is proposed to transform Li2CO3 into Li3PO4 and LiF in LiPF6 solution under 60 °C. It is found that the formation of Li3PO4 during LLZTO pretreatment facilitates rapid Li‐ion transport and enhances ionic conductivity, and the LLZTO/PAN composite polymer electrolyte shows the highest Li‐ion transference number of 0.63. Additionally, the dense LiF layer serves to safeguard the internal garnet solid electrolyte against solvent decomposition‐induced chemical adsorption. Symmetric Li/Li cells assembled with treated LLZTO/PAN composite electrolyte exhibit a critical current density of 1.1 mA cm−2 and a long lifespan of up to 700 h at a current density of 0.2 mA cm−2. The Li/LiFePO4 solid‐state cells demonstrate stable cycling performances for 141 mAh g−1 at 0.5 C, with capacity retention of 93.6% after 190 cycles. This work presents a novel approach to converting waste into valuable resources, offering the advantages of simple processes, and minimal side reactions.

High Young’s Modulus Li6.4La3Zr1.4Ta0.6O12-Based Solid Electrolyte Interphase Regulating Lithium Deposition for Dendrite-Free Lithium Metal Anode

“…Figure S7a is the XPS diagram of La 3d. Both the binding energies of 851.8 and 855.6 eV belong to La 3d 3/2 , and the 835.1 and 838.8 eV belong to La 3d 5/2 . , The two peaks corresponding to Zr 3d are Zr 4+ Zr 3d 3/2 at 184.4 eV and Zr 4+ Zr 3d 5/2 at 182.04 eV (Figure S7b). , Ta 4f corresponds to Ta 4f 7/2 at 25.7 eV and Ta 4f 5/2 at 27.65 eV (Figure S7c) . The Li 1s spectrum has two peaks at 55.29 and 52.98 eV, which are the spectra of LLZTO and metal Li (Figure S8a) .…”

“…Both the binding energies of 851.8 and 855.6 eV belong to La 3d 3/2 , and the 835.1 and 838.8 eV belong to La 3d 5/2 . 52,53 The two peaks corresponding to Zr 3d are Zr 4+ Zr 3d 3/2 at 184.4 eV and Zr 4+ Zr 3d 5/2 at 182.04 eV (Figure S7b). 54,55 Ta 4f corresponds to Ta 4f 7/2 at 25.7 eV and Ta 4f 5/2 at 27.65 eV (Figure S7c).…”