Density functional theory study of monoclinic Li3Co2SbO6 for Li ion battery applications

Monoclinic Li3Co2SbO6 has been studied with an aim to use it as Li ion battery electrode materials, using Density functional theory (DFT). Li3Co2SbO6 crystallizes with space group C2/m (space group number 12). The deintercalation process can proceed in two different ways viz., (1) Li3 & RARR; Li1 & RARR; Li0 and (2) Li3 & RARR; Li2 & RARR;Li0. However, there is no phase change in accordance with Li2 & RARR; Li1, due to its unique structural arrangements. The formation energy of Li2Co2SbO6 and LiCo2SbO6 with respect to the two extreme phases viz., Li3Co2SbO6 and Co2SbO6 were evaluated and respectively found to be 0.0462 eV and 0.025 eV, which suggests that it may not be possible to extract all the Li+ ions from pristine Li3Co2SbO6. Also, electronic band gap -3.28 eV of Li3Co2SbO6 is less than the same for LiFePO4. A stable voltage plateau was achieved with -4.1 V for extraction of multiple Li+ ions from Li3Co2SbO6. Also, a 2D diffusion path with path length -3.1 A was identified in Li3Co2SbO6. With lower band gap, high voltage and 2D diffusion path in comparison to LiFePO4 (with 1D diffusion path), it may be possible that Li3Co2SbO6 may surplus the efficiency of LiFePO4 if it would become possible to extract multiple Li+ ions from it.

Automated summary

The potential of monoclinic Li3Co2SbO6 as a lithium-ion battery electrode material was studied using density functional theory (DFT). Li3Co2SbO6 crystallizes in space group C2/m (space group number 12). The deintercalation process can proceed in two different ways: Li3→Li1→Li0 and Li3→Li2→Li0. However, there is no phase change with Li2→Li1 due to its unique structural arrangements. The formation energies of Li2Co2SbO6 and LiCo2SbO6 were evaluated and found to be 0.0462 eV and 0.025 eV, respectively, suggesting that it may not be possible to extract all Li+ ions from pristine Li3Co2SbO6. The electronic band gap of Li3Co2SbO6 (-3.28 eV) is lower than that of LiFePO4. A stable voltage plateau of -4.1 V was achieved for the extraction of multiple Li+ ions from Li3Co2SbO6. Additionally, a 2D diffusion path with a path length of -3.1 A was identified in Li3Co2SbO6. It is possible that Li3Co2SbO6 may exceed the efficiency of LiFePO4 if multiple Li+ ions can be extracted from it.