The effects of Fe/Al co-modified Ni-rich Li[Ni1-x-yCoxMny]O2 for enhancing electrochemical performance

Various impurities such as Cu, Al, and Fe can be incorporated in the leachate of spent lithium-ion batteries (LIB) after a conventional acidic leaching process. Here, we synthesize Fe/Al co-modified Ni-rich Li[Ni1-x-yCoxMny]O2 (NCM) cathode materials via a coprecipitation reaction for Fe doping and the subsequent calcination process for additional Al doping. The purpose of this work is to seek a potential of utilizing the positive effects of impurity elements for improving the LIB performance of Ni-rich NCM. The physicochemical properties of cathode materials are compared by scanning electron microscopy, energy dispersive spectroscopy, inductively coupled plasma optical emission spectroscopy and X-ray diffraction analysis. Electrochemical analyses including galvanostatic intermittent titration technique, differential capacity curves from cycling data are systematically performed to assess the effects of the sequential doping processes. It is found that an Al doping content of 1% in Fe-doped NCM is optimal in terms of rate and cycle performances. This study proposes a rational design for upgrading the resynthesized Ni-rich NCM cathode materials from the leachate of spent LIBs. [Display omitted] •Fe and Al are major impurity elements in Li-ion battery (LIB) recycling.•Fe and Al are incorporated into LiNiCoMnO2 by coprecipitation and calcination.•Optimal Al doping content is 1% in terms of cyclability and rate capability.•Enhanced LIB performance is due to reduced polarization and faster Li diffusion.•Fe and Al co-modification can upgrade resynthesized cathode materials.