First Total H+/Li+ Ion Exchange in Garnet-Type Li5La3Nb2O12 Using Organic Acids and Studies on the Effect of Li Stuffing

Garnet-type Li(5+x)Ba(x)La(3-x)Nb(2)O(12) (x = 0, 0.5, 1) was prepared using a ceramic method, and H(+)/Li(+) ion exchange was performed at room temperature using organic acids, such as CH(3)COOH and C(6)H(5)COOH, as proton sources. Thermogravimetric analysis showed that H(+)/Li(+) ion exchange was nearly (100%) completed using the x = 0 member with CH(3)COOH, while it proceeded to about 40% for x = 0.5 and 13% for x = 1. In C(6)H(5)COOH, proton exchange proceeded to about 82% for x = 0, ∼40% for x = 0.5, and ∼25% for x = 1. Similar proton-exchange trends were reported in H(2)O, where ion exchange occurs more readily for garnets with lower Li content in Li(5+x)Ba(x)La(3-x)Nb(2)O(12), that is, when excess Li ions preferentially reside in the tetrahedral sites of the garnet structure.