A new ternary co-free layered cathode, Li[Ni1-x-yTixAly]O2, for high-energy lithium-ion batteries

Abstract

For the sustainable development of Li[NixCoyMn1−x−y]O2 and Li[NixCoyAl1−x−y]O2 cathodes, reducing the reliance on cobalt, which is extremely expensive with a fluctuating price and supply uncertainty, is considered essential. In this study, we propose a highly stable Co-free Ni-rich layered cathode developed through a new doping strategy that incorporates heteroelements at different doping stages, including the introduction of Ti during Ni(OH)2 synthesis and doping excess amounts of Al during the lithiation step. The multi-stage engineering strategy guarantees structural durability and electrochemical cycling stability of the inherently unstable LNO to a commercially viable level. Combined with particle surface protection, the Li[Ni0.951Ti0.008Al0.041]O2 cathode retains 72.0% of its initial capacity after 3500 cycles, which is unprecedented among previously reported Co-free cathodes. The proposed Co-free cathodes can meet the energy density required for next-generation electric vehicles, as the cathode delivers 890 Wh kgcathode-1, and presents a clear breakthrough for the development of commercially viable LNO cathode.