Compatibility Issues Between Electrodes and Electrolytes in Solid-State Batteries

Solid-state batteries have recently attracted significant attention because of their advantages compared with conventional batteries employing liquid electrolytes. Remarkable success has been achieved in the discovery of ceramic alkali superionic conductors as electrolytes in solid-state batteries; however, obtaining a stable interface between these electrolytes and electrodes is difficult. Only limited studies on the compatibility between electrodes and solid electrolytes have been reported, partially because of the need for expensive instrumentation and special cell designs. Without simple yet powerful tools, these compatibility issues cannot be systematically investigated, thus hindering the generalization of design rules for the integration of solid-state battery components. In this work, we present a methodology that combines density functional theory (DFT) calculations and simple experimental techniques such as X-ray diffraction(XRD), simultaneous differential scanning calorimetry and thermal gravimetric analysis (SDT), and electrochemistry to efficiently screen the compatibility of numerous electrode/electrolyte pairs. Employing a Na solid-state system as an example, we demonstrate the efficiency of our method by finding the most stable system (NaCrO 2 |Na 3 PS 4 |Na-Sn) within a selected chemical space (more than 20 different combinations of electrodes and electrolytes). Important selection criteria for the cathode, electrolyte, and anode in solid-state batteries are also derived from this study. This work has two important implications for the future studies in the related fields: (1) the study of the stability window of the electrolyte and the reaction conditions and products of the reactions between electrode and electrolyte provide an essential guide for integrating all-solid-state battery components; and (2) this current method can significantly accelerate the expansion of the electrolyte/electrode compatibility database. Figure 1