Crack-free single-crystal LiNi0.83Co0.10Mn0.07O2 as cycling/thermal stable cathode materials for high-voltage lithium-ion batteries

The needs for lightweight portable electronic devices and long-duration electric vehicles impel the development of high-energy lithium-ion batteries (LIBs). As a promising cathode material, the high nickel content (x) and cutoff voltage facilitate to increase energy density of LiNixCoyMnzO2 (x+y+z=1) whereas they impair cycling and thermal stability. Herein, we first synthesize crack-free single crystal LiNi0.83Co0.10Mn0.07O2 (SC-NCM) materials, which possess superior cycling and thermal stability at high voltages by decreasing the inter-granular fracture induced by anisotropic volume changes to retain the interior particle morphology integrity during long charge–discharge processes. Specifically, SC-NCM in full cells between 3.00 V and 4.35 V delivers reversible capacity of 167.0 mAh g−1 and capacity retention of 84.8% after 400 cycles at 0.5 C/25 °C, which are far larger than 107.7 mAh g−1 and 54.1% of conventional polycrystalline LiNi0.83Co0.10Mn0.07O2 (PC-NCM). The enhanced high-voltage cyclability of SC-NCM is attributed to lower transition metal dissolution, higher anti-crack performances, better phase transition reversibility and smaller volume change, revealed by in-situ X-ray diffraction and differential capacity curves between 3.0 and 4.9 V. The SC-NCM has better floating charge durability than PC-NCM at high temperature by depressing side reactions between cathode and electrolyte, and formation of nickel dendrite-induced internal short dots.