Accelerated Development of High Voltage Li‐Ion Cathodes

Abstract

Abstract High voltage cathodes are attractive for high energy density Li‐ion batteries. However, candidates such as LiCoPO 4 have presented numerous challenges stemming from poor electronic/ionic conductivities such that typical solutions involving nanosizing result in extremely poor cycling performance. Here, high‐throughput methods are applied to develop near‐micron sized carbon‐coated LiCoPO 4 with improved energy density and capacity retention. In total, 1300 materials with 46 different substituents are synthesized and characterized. A number of substituents show greatly improved capacity (e.g., 160 mAh g −1 for 1% indium (In) substitution vs 95 mAh g −1 for the pristine). However, co‐doping is required to improve extended cycling. Li 1–3x Co 1–2x In x Mo x PO 4 is found to be particularly effective with dramatically improved cycling (as high as 100% after 10 cycles, vs ≈50% in unsubstituted). While In improves the electronic conductivity of the carbon‐coated materials, molybdenum (Mo) co‐doping gives larger particles. DFT calculations show that Mo impedes the formation of Li/Co antisite defects.