Hydrogen absorption and desorption characteristics of H2O-uptake LiCoO2 materials at room temperature

Herein, the hydrogen absorption and desorption characteristics of H2O-uptake by LiCoO2 materials at room temperature and the most stable trapping sites of H in LiCoO2 were investigated; this was achieved by using weight gain (WG) measurement, elastic recoil detection (ERD) in ambient air, gas chromatography (GC), and first-principles calculations with a density functional theory code. The WG results and ERD spectra revealed that the H concentration in LiCoO2 increased when soaked in H2O at 288 K for 2 min. The GC analysis revealed that hydrogen molecules (H2) were released from the H2O-uptake LiCoO2 materials at annealing temperatures less than 523 K. In addition, it was found by the first-principles calculations that H atoms dissociated from H2O tend to preferentially occupy lithium (Li) substitution sites in LiCoO2. These results indicate that the LiCoO2 material has a significant impact on H storage at room temperature due to H2O splitting to product H2.