Heating-time independent densification of LATP via cold sintering process

Abstract

The Cold Sintering Process has been used to sinter Li_1.3Al_0.3Ti_1.7(PO₄)₃ powder (LATP) initially mixed with 15 wt% of a solution of acetic acid 3 m as Transient Liquid Phase (TLP). The effect of variables such as green density, heating rate, sintering temperature, dwell time and the operating pressure on the densification of LATP via CSP has been thoroughly analysed. The operating pressure shows no effect on the green density above 450 MPa. The heating rates, thus the heating time, do not modify the densification behavior of LATP Solid-State Electrolytes (SSEs) but a decomposition reaction takes place at temperatures above 180 ºC. This reaction depends on the TLP amount still present in the pores, and at higher pressures (P > 450 MPa) this decomposition effect on densification is reduced as the pore volume becomes smaller. For the first time in the CSP, a linear dependence of relative density on temperature is demonstrated.