Novel nanocrystalline mixed conductors were obtained by thermal nanocrystallisation of lithium iron -borate glasses (nominally LiFeBO3) prepared via melt-quenching method. After heat treatment, a glass-ceramics consisting of FeBO3 and LiFeBO3 phases was obtained. Grain sizes, estimated using Scherrer formula, were 45-50 nm and 70-80 nm, respectively. Value of electrical conductivity of the initial glass was estimated as 5.8.10(-12) S cm(-1). After annealing at 475 degrees C, a growth by a factor 2.4.10(6) was observed, leading to final conductivity value 1.4.10(-5)S cm(-1) at room temperature. The activation energy of electronic conductivity was lowered from 0.81 eV for glass to 0.18 eV for thermally treated material. (C) 2016 Elsevier B.V. All rights reserved.