Ab-initio modelling of new cathode material for Li-ion battery based on the Ti substituted Li_2Fe(SO_4)_2

摘要

This work demonstrates the battery-related properties of Li_2Fe(SO_4)_2 and its Fe site Ti substituted derivatives (Li_2Ti_(0.5)Fe_(0.5)(SO_4)_2 and Li_2Ti(SO_4)_2) using ab-initio calculations. The calculated voltage profile of all these systems clearly indicates the increase of voltage with delithiation. Even though the average voltage values of Ti-substituted systems gradually changes with the Ti concentration, they are still in the range of requirement for a good cathode material. In most of the cases, Ti substitutions increase the specific capacity and energy density of Li_2Fe(SO_4)_2. The negative enthalpy of formation implies that all the considered systems are thermodynamically stable. These results indicate that Ti-substituted Li_2Fe(SO_4)_2 could be a potential cathode material for rechargeable Li-ion batteries.