Origin of electrochemical cycling stability induced by calcination temperature for cobalt-free nickel-rich cathodes†

Cobalt-free Nickel-rich cathodes LiNi_0.9Mn_0.1O₂ were synthesized at different temperatures. Electrochemical cycling tests revealed that low-temperature synthesized samples showed a markedly enhanced cycling stability compared to those synthesized at higher temperatures. Our analysis suggests that the stable discharge capacity of the low-temperature synthesized samples can be attributed to a slightly greater cation mixing degree and smaller primary particle size. These factors help alleviate stress concentration during cycling, thereby reducing intergranular cracks and mitigating side reactions, which are evidently contrasting in samples synthesized at higher temperatures. Meanwhile, the residual Li is not a significant factor that influences electrochemical performance in our study. Therefore, the calcination temperature largely influences the electrochemical performance of polycrystalline cathodes by affecting the lithiation process and controlling the growth of grain size.