Investigation of Solid Electrolyte Interface Formation in Li3as Electrode Material in a Solid-State Battery Configuration

Abstract

Solid state batteries have gained attention due to the promise of safe operation of battery at high voltage and for longer duration. Solid electrolytes may also help to stabilize conversion electrodes for higher energy density. Arsenic alloys are rarely studied, but several may be interesting as the negative electrode, for example, FeAs, As/C, and InAs.1 The fact that the cost per pound of Arsenic is less than the counterpart negative electrode candidates like Si, Ge, In, Pb, Ti, and V is advantageous.2 In this context, we chose Li3As as a negative electrode material in a solid-state battery configuration. The intrinsic high electronic conductivity of Li3As and conversion reaction mechanism providing a high energy density are the reasons behind selecting Li3As for studying the cycling and interface stability with a Li-P-S based solid electrolyte. The solid-state battery was cycled at different temperatures and the resultant pellet was dissected for analyzing the interface layer formed. The battery that has the iodide doped solid electrolyte performed well in terms of electrochemical cycling properties compared to the undoped electrolyte. An iodide rich layer between the solid electrolyte and Li3As electrode formed within few cycles. This thin iodide rich layer is responsible for the stable performance of the solid-state battery for over 100 cycles. Acknowledgement: This work was supported by the Assistant Secretary for Energy Efficiency and Renewable Energy, Office of Vehicle Technologies of the U. S. Department of Energy under the Advanced Battery Materials Research Program. Synthesis of the electrolyte was conducted as part of user proposal at ORNL’s Center for Nanophase Materials Sciences (CNMS), which is an Office of Science User Facility.