Preparation of lithium indium oxide via a rheological phase route and its electrochemical characteristics in LiOH and Li₂SO₄ solutions

Abstract Submicrometer‐sized lithium indium oxide (LiInO₂) powder via a rheological phase method using trilithium citrate tetra hydrate (C₆H₅Li₃O₇ · 4H₂O) and indium oxide (In₂O₃) has been prepared in this work for the first time. The optimal pyrolyzing temperature range to prepare crystalline LiInO₂ is between 650 and 900 °C, which was confirmed by thermal gravimetric and differential thermogravimetric analysis of the precursor and X‐ray diffraction analysis. The pure phase LiInO₂ sample obtained has a uniform particle morphology and submicrosize, which was observed by scanning electron microscopy. The electrochemical studies show that a new pair of cathodic and anodic peaks at 0.23 and 0.38 V (vs. saturated calomel electrode) was obviously observed from the cyclic voltammetry curve of LiInO₂ in 1 M LiOH solution, indicating a battery characteristic of the material in this electrolyte. While in 1 M Li₂SO₄ solution, the sample presents a supercapacitive characteristic within the same potential range. The reasons for different electrochemical behaviors in these two electrolytes can be attributed to the fact that the reaction of lithium ion insertion/extraction into/out of a LiInO₂ electrode takes place in the bulk material in LiOH electrolyte solution, whereas it takes place on the electrode/electrolyte interface for Li₂SO₄ electrolyte case.