Targeted doping enables multi-scale stress regulation for high reliable Ni-rich layered cathodes

As one of the most promising positive electrode materials for power batteries, Ni-rich layered cathodes have recently attracted phenomenal attention due to their high energy density nature. However, Ni-rich layered cathodes suffer from severely intrinsic chemo-mechanical instabilities and insufficient service life, which is exacerbated further when the batteries are operated at a high voltage. Here, by carefully investigating the single element doping chemistry, a targeted doping strategy that combines advantages of multiple elements is proposed to suppress strain accumulation during electrochemical cycling. The bulk compatible low-valence elements (LVEs) reduce the volumetric strain and stabilize the highly delithiated crystal structure through bulk doping. The high-valence elements (HVEs) regulate the growth direction of primary particles and form a radial structure that is more conducive to strain release. As a result, the well-designed Ni-rich cathodes deliver excellent electrochemical and structural stability with a capacity retention of 94.8 % at 1 C after 200 cycles within 2.7–4.5 V (versus Li/Li⁺) in half cell and 93.3 % at 1 C after 500 cycles within 3.0–4.25 V (versus graphite) in single layer full cell. This work provides a universal strategy for suppressing chemo-mechanical degradation in intercalation electrodes and paves the way for next generation high-energy-density cathodes.