Scientific Achievement
Systematic evaluations were performed to screen for feasible MV cathode candidates. Spinel MgCr2S4, MgTi2S4, MgMn2S4 and CaCr2S4 were found as the most promising systems for multivalent cathode applications due to their facile cation mobility (<650meV) among the 3d transition–metal sulfur spinel compounds.
Significance and Impact
Our study provides guidance for future experimental multivalent cathode development and design, as well as insights into how the relevant properties can be tuned by both cation and anion substitution, the latter one by compared to earlier oxide spinel work.
Research Details
- Insertion voltage, capacity, thermodynamic stability, intercalating cation site preference as well as the cation mobility were evaluated using first-principles calculations.
- Site energy difference between tetrahedral and octahedral sites is used as an indicator to estimate a lower bound of the migration activation energy.
- The underlying mechanism of cation mobility was discussed and explained.
- Possible experimental synthesis routes were proposed.
- Extensive comparison and benchmarking to demonstrate the accuracy and reliability of the theory applied.
