Extended fast-charging life of ultrahigh-Ni layered oxides by adjusting the current density during the H2→H3 phase transition

Abstract

High-energy-density lithium (Li)-ion batteries (LIBs) with excellent fast-charging ability are urgently needed for electric vehicles (EVs). Ultrahigh-Ni (Ni≥0.8) layered oxides (UNLO) can directly endow LIBs with a high energy density. However, cracks induced by the H2→H3 phase hamper the fast-charging application of UNLO. Spinel cathode materials have excellent power performance and a higher and flatter equilibrium potential. We are the first authors to propose the use of spinel cathode materials to adjust the local current density of hybrid cathodes, demonstrating that reducing the current density during the H2→H3 phase transition is an effective strategy for prolonging the fast-charging life of ultrahigh-Ni layered oxides. Optimized hybrid cathodes with a commercial-level areal capacity (∼2.6 mAh cm−2) are employed to fabricate a multilayer pouch cell (>2 Ah) with graphite-based anodes. The cells achieve an ultrahigh energy density of 224 Wh kg−1 and retain 89.7% of their initial capacity after 500 cycles at a high charging rate of 3C (20 min). This cost-effective and time-efficient approach is suitable for scaling up to existing LIBs manufacturing facilities and will be crucial for accelerating the commercialization of ultrahigh-energy-density LIBs with excellent fast-charging ability.