(381b) Impact of Long-Lasting Battery Cathodes on Fast Charge Capability

Ni-rich layered cathodes suffer from severe degradation driven by microcracking, lithium trapping, and structural instability. Here, we report a core-shell gradient plus shell concentration gradient Li[Ni0.9Co0.05Mn0.05]O2 (CSGPS90) cathode that addresses these challenges through a Ni-rich core for high energy density and a Mn-rich shell for enhanced mechanical and chemical stability. Compared to conventional NCM90, CSGPS90 demonstrates significantly improved capacity retention (88.8% vs. 80.6% after 200 cycles under 3C fast-charging), rate capability, and structural integrity. Moreover, FIB-TOF SIM/SEM imaging of the materials, performed in a charged state and after 1000 cycles, reveals that NCM90 is plagued with localized Li+ trapped along microcracks, indicative of severe internal degradation and NiO-like rock-salt phase formation. In contrast, CSGPS90 exhibits uniform Li+ extraction with no significant trapped Li+, enabled by its Mn-enriched shell that suppresses microcrack propagation and surface reconstruction. These results establish microstructural gradient engineering as a powerful strategy to stabilize Ni-rich cathodes for high-energy, fast-charging applications with long-term durability under realistic operating conditions.