Preparation of macroporous Li2ZrO3 monoliths via an epoxide-mediated sol–gel process accompanied by phase separation

Monolithic lithium zirconate (Li2ZrO3) with well-defined co-continuous macropores was successfully prepared via an epoxide-mediated sol–gel process accompanied by phase separation. Appropriate choice of poly(ethylene oxide) as a phase separation inducer and propyleneoxide as a gelation agent allows the production of continuous macroporous gel monolith. The dried gels are amorphous and tetragonal lithium zirconate (t-Li2ZrO3) precipitates firstly at 650 °C. The phase transformation from t-Li2ZrO3 to monoclinic lithium zirconate (m-Li2ZrO3) initiates at 900 °C and completes when elevating the calcination temperature to 1000 °C. The macroporous structure is retained after heat-treatment, and the t-Li2ZrO3 monolith with porosity of 43.3% and dense solid skeletons is obtained.