The photorefractive effect is investigated in nominally pure a-LiIO3 crystals within the 333-514.5 nmspectral range. In the temperature range of 180 K-240 K, i.e., the temperature range of the superionic phasetransition, a dramatic decrease of the diffraction efficiency by a factor 100 is observed. This can be explainedby the formation of an ionic complementary grating having an activation energy for thermal erasure of 0.3260.03 eV. Thermal fixing can be achieved by holographic recording at temperatures below about 180 K,developing the complementary grating at room temperatures, and finally recovering the complementary gratingbelow 180 K. In contrast to the assumptions made for the thermal fixing process in other crystals, e.g.,LiNbO3, the mobile ionic species in a-LiIO3 are mainly lithium ions.