A novel Na substituted Li3-xNaxPS4 mixed ions solid electrolyte for all solid-state lithium batteries

Abstract

In this work, a novel Na substituted Li3-xNaxPS4 mixed-ions solid electrolyte is prepared by ball milling process. Various physio-chemical characterization techniques such as high-power X-ray diffraction, laser Raman spectroscopy, field emission scanning electron microscopy, and X-ray photoelectron spectroscopy are adopted to analyse structural characteristics, surface morphology, particle size, and chemical composition of the prepared materials. Electrochemical impedance spectroscopy technique is used to calculate the ionic conductivity of the prepared solid electrolytes. The prepared Li2.8Na0.2PS4 solid electrolyte is exhibited high ionic conductivity of 3.6 × 10−4 S cm−1 at room temperature. In addition, Li2.8Na0.2PS4 solid electrolyte shows excellent stability against lithium metal. The fabricated, In/Li2.8Na0.2PS4/NCM/In 2032 type coin cell shows a specific capacity of 99.1 mAh g−1 at current density of 0.1C between the potential of 2.38 V and 3.68 V with ~65% specific capacitance retention after 25 cycles. This study proves that Na substitution provides high ionic conductivity and good electrochemical performance to obtain promising electrolyte material for future all solid-state battery applications.