Spray pyrolysis feasibility of tungsten substitution for cobalt in nickel-rich cathode materials

Cobalt (Co) serves as a stabilizer in the lattice structure of high-capacity nickel (Ni)-rich cathode materials. However, its high cost and toxicity still limit its development. In general, it is possible to perform transition metal substitution to reduce the Co content. However, the traditional coprecipitation method cannot satisfy the requirements of multielement coprecipitation and uniform distribution of elements due to the differences between element concentration and deposition rate. In this work, spray pyrolysis was used to prepare LiNi_0.9Co_0.1−xW_xO₂ (LNCW). In this regard, the pyrolysis behavior of ammonium metatungstate was analyzed, together with the substitution of W for Co. With the possibility of spray pyrolysis, the Ni–Co–W-containing oxide precursor presents a homogeneous distribution of metal elements, which is beneficial for the uniform substitution of W in the final materials. It was observed that with W substitution, the size of primary particles decreased from 338.06 to 71.76 nm, and cation disordering was as low as 3.34%. As a consequence, the prepared LNCW exhibited significantly improved electrochemical performance. Under optimal conditions, the lithium-ion battery assembled with LiNi_0.9Co_0.0925W_0.0075O₂ (LNCW-0.75mol%) had an improved capacity retention of 82.7% after 200 cycles, which provides insight into the development of Ni-rich low-Co materials. This work presents that W can compensate for the loss caused by Co deficiency to a certain extent.