Li-ion batteries (LIBs) today face the challenge of application in electrified vehicles (xEVs) which require increased energy density, improved abuse tolerance, prolonged life, and low cost. LIB technology can significantly advance through more realistic approaches such as: i) stable high-specific-energy cathodes based on Li Ni Co Mn O (NCM) compounds with either Ni-rich (x = 0, y → 1), or Li- and Mn-rich (0.1 < x < 0.2, w > 0.5) compositions, and ii) chemically active separators and binders that mitigate battery performance degradation. While the stability of such cathode materials during cell operation tends to decrease with increasing specific capacity, active material doping and coatings, together with carefully designed cell-formation protocols, can enable both high specific capacities and good long-term stability. It has also been shown that major LIB capacity fading mechanisms can be reduced by multifunctional separators and binders that trap transition metal ions and/or scavenge acid species. Here, recent progress on improving Ni-rich and Mn-rich NCM cathode materials is reviewed, as well as in the search for inexpensive, multifunctional, chemically active separators. A realistic overview regarding some of the most promising approaches to improving the performance of rechargeable batteries for xEV applications is also presented.

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High-energy cathode materials that are Li- and Mn-rich lithiated oxides—for instance, 0.35Li2MnO3.0.65LiNi0.35Mn0.45Co0.20O2 (HE-NCM)—are promising for advanced lithium-ion batteries. However, HE-NCM cathodes suffer from severe degradation during cycling, causing gradual capacity loss, voltage fading, and low-rate capability performance. In this work, we applied an effective approach to creating a nano-sized surface layer of Li2SO4 on the above material, providing mitigation of the interfacial side reactions while retaining the structural integrity of the cathodes upon extended cycling. The Li2SO4 coating was formed on the surface of the material by mixing it with nanocrystalline Li2SO4 and annealing at 600 °C. We established enhanced electrochemical behavior with ~20% higher discharge capacity, improved charge-transfer kinetics, and higher rate capability of HE-NCM cathodes due to the presence of the Li2SO4 coating. Online electrochemical mass spectrometry studies revealed lower CO2 and H2 evolution in the treated samples, implying that the Li2SO4 layer partially suppresses the electrolyte degradation during the initial cycle. In addition, a ~28% improvement in the thermal stability of the Li2SO4-treated samples in reactions with battery solution was also shown by DSC studies. The post-cycling analysis allowed us to conclude that the Li2SO4 phase remained on the surface and retained its structure after 100 cycles.