In-situ construction of niobium coating/substitution Ni-rich cathodes to enhance lithium ion battery performance

The high nickel stoichiometry in Li[Ni 0.8 Co 0.1 Mn 0.1 ]O 2 (NCM811) cathode materials, while advantageous for specific capacity enhancement, introduces concomitant challenges including (i) surface instability due to high surface residual Li compounds (RLCs) content, and (ii) accelerated structural degradation and deleterious phase transitions during electrochemical cycling. To address these challenges, NCM811 was treated with an aqueous solution of ammonium niobium oxalate, which not only reduced the RLCs content on the surface, but also in-situ constructed a LiNbO 3 coating layer on the surface of the NCM811 materials after the re-calcination process. Within a potential range of 2.75–4.3 V at 0.5C and 25 °C, the Nb-modified NCM811 materials exhibit the advantages of improved specific capacity of 215.3 mAh g −1 and excellent capacity retention of 92.3 % after 200 cycles. This integrated approach synergistically combines wet coating with re-calcination treatment to achieve dual modification of NCM811 cathodes-simultaneously reducing RLCs while enabling in-situ construction of a lattice-doped LiNbO 3 coating layer, demonstrating exceptional potential for scalable industrial implementation through its combined performance enhancement and process compatibility.