Preservation of dopant induced high ionic conductivity in cold sintered Bi2O3 ceramic family

Bi 2 O 3 -based ceramics are promising functional materials for electrochemical devices. However, conventional high-temperature sintering (HTS) is energy intensive and can cause interfacial reactions or mechanical failure. In this work, pure Bi 2 O 3 and Er-, Nb-, and Ba-doped compositions were fabricated via the cold sintering process (CSP) at 250 °C. All samples achieved relative densities above 90 %, with pure and Ba-doped ceramics approaching unity. Most compositions remained single-phase after CSP, whereas the Ba-doped ceramic showed slight phase segregation. Analysis of the FTIR and TG–DSC results revealed the CSP mechanism, in which bismuth acetate and oxyacetate form and assist the densification process. CSP ceramics exhibited high oxide ion or electronic conduction that was comparable to their HTS counterparts. The results confirm the feasibility of applying CSP to Bi 2 O 3 -based ceramics, paving the way for the fabrication of advanced composite materials and complex devices.