Promoting Cyclability, Rate Performance, and Safety\nof LiNi<sub>0.85</sub>Co<sub>0.13</sub>Al<sub>0.02</sub>O<sub>2</sub> by <i>in Situ</i> Forming LiTi<sub>2</sub>(PO<sub&gt

LiNi<sub>0.85</sub>Co<sub>0.13</sub>Al<sub>0.02</sub>O<sub>2</sub> (NCA) is\nattractive for high capacity but faces challenges like\nstability and thermal runaway. To address the issues, quasi-spherical\nnanoscaled LiTi<sub>2</sub>(PO<sub>4</sub>)<sub>3</sub> (LTP), a fast\nion conductor with a negative thermal expansion property, is synthesized\nand utilized to modify NCA. The effects of LTP on the performance\nand deformation of NCA are evaluated using multifarious methods. NCA\nmodified with 7 wt % LTP exhibits the best performance, and its discharge\ncapacities can retain 167.4 and 160.4 mAh g<sup>–1</sup> at\n25 and 60 °C after 100 cycles, respectively, much higher than\nthose of NCA. Furthermore, the structural integrity and thermal stability\nof NCA are significantly improved, and the Li<sup>+</sup> diffusion\ncoefficient is increased around 70.2%, while the strain and <i>R</i><sub>ct</sub> are declined about 77.3% and 65.7%, respectively.\nLTP and carbon (LTP@C) <i>in situ</i> form a shell to cover\nNCA particles during cycles. The electrode reaction process, interface,\nand mechanism are discussed. It represents a strategy to update energy\nmaterials.