Synergistic Microstructural Engineering of LiNi 0.8 Co 0.1 Mn 0.1 O 2 Cathodes via pH-Controlled Crystallographic Orientation of Ni 0.8 Co 0.1 Mn 0.1 (OH) 2 Precursors

Commercialized LiNi0.8Co0.1Mn0.1O2 cathode materials synthesized by the coprecipitation-calcination two-step process have been widely used in electric vehicles. However, the random arrangement of nanoprimary particles aggravates the accumulation of anisotropic stress and destroys the structural stability of microsized secondary particles, leading to inferior cycling performance. Here, the orderly arrangement of nanoprimary particles of cathode LiNi0.8Co0.1Mn0.1O2 materials is carried out by precisely controlling the pH values of a Ni0.8Co0.1Mn0.1(OH)2 precursor during the coprecipitation process.. When the pH is controlled at 11.4 during coprecipitation, more (001) planes are exposed in Ni0.8Co0.1Mn0.1(OH)2 precursor, and the as-prepared LiNi0.8Co0.1Mn0.1O2 material shows orderly arranged nanoprimary particles and lowest degree of Ni/Li cation mixing, thus delivering excellent electrochemical performance. LNCM-11.4 exhibits a high initial discharge capacity of 228.8 mAh g-1 at 0.1 C and a 92.9% capacity retention after 100 cycles at 1 C within a 2.8-4.3 V range. The elevated electrochemical properties can be ascribed to the synergistic microstructural engineering of LNCM-11.4. The low degree of Ni/Li mixing maintains the structural stability and unique orderly arrangement of nanoprimary particles, which facilitates the diffusion of Li-ions and alleviates accumulation of antistrophic pressure. This work demonstrates that pH-controlled precursor crystallization enables synergistic microstructural engineering, which provides a feasible strategy for the rational design of high-performance Ni-rich cathode materials.