Coaxial electrospinning-driven elemental gradient engineering for voltage decay suppression in Li-rich cathodes

Abstract

Li-rich Mn-based layered oxides (LRMs) are promising high-capacity cathodes for next-generation Li-ion batteries, yet their commercialization is hindered by structural instability, voltage decay, and Mn dissolution. This work develops a transition metal gradient-structured LRM (D-LRM) via coaxial electrospinning, integrating Mn/Ni/Co concentration gradients and spinel-layered heterostructures. The innovative design elevates the average Mn oxidation state to +3.60, effectively suppressing Jahn–Teller distortion while mitigating phase transitions via synergistic interfaces between spinel and layered structures. D-LRM exhibits a high initial coulombic efficiency of 93.61%, 76.54% capacity retention after 200 cycles, and a low voltage decay rate of 2.705 mV per cycle, outperforming conventional uniaxial electrospinning. This strategy provides a scalable pathway to design durable, high-energy cathodes, addressing the critical barriers for practical applications in electric vehicles and grid storage systems.