Li7La3Zr2O12 coated LiNi0.87Co0.05Mn0.05Al0.03O2 for lithium-ion cells with enhanced performance

•Quaternary Ni-rich LiNi0.87Co0.05Mn0.05Al0.03O2 as the combination of NCM and NCA is successfully synthesized.•Li7La3Zr2O12 layer could relieve cathode against HF erosion and enhance the cycling performance.•Li7La3Zr2O12 with Li-ion conductor contributes to improving the high rate performance of cathode.•High crystal structure and thermal stability of cathode are obtained by the Li7La3Zr2O12 coating.•1 wt.% Li7La3Zr2O12 coated LiNi0.83Co0.06Mn0.06Al0.05O2 demonstrates the excellent electrochemical properties and safety performance. The Ni-rich layered cathodes have demonstrated the great advantage on pushing the limit of lithium-ion batteries to higher energy density but suffer from the poor cycling performance and unstable safety reliability. Surface covering is a practical and effective strategy to ameliorate the drawbacks. In the work, the Li7La3Zr2O12 widely used in solid electrolyte owing to the high Li+ conductivity is applied to cover on the surface of LiNi0.87Co0.05Mn0.05Al0.03O2 to enhance its electrochemical properties and thermal stability, which are confirmed by the X-ray diffraction, scanning electron microscope, energy disperse spectroscope, transmission electron microscope, X-ray photoelectron spectroscope, differential scanning calorimetry and charge-discharge tests. As a consequence, the Li7La3Zr2O12 coated cathodes demonstrate the significant promotion on high rate capability, discharge capacity at high and low temperature, long cycling stability and safety performance. Such a big elevation could be attributed that the Li7La3Zr2O12 coating strategy effectively protects the cathode particles against the electrolyte attack, maintains the particles morphology integrality during cycling and enhances the thermal stability of pristine cathode. The 1 wt.% Li7La3Zr2O12 coated Ni-rich quaternary LiNi0.87Co0.05Mn0.05Al0.03O2 is covered by a shell of lithium conducting Li7La3Zr2O12 layer around the cathode particles with a thickness of 6∼12 nm. After 500 cycles at 25 °C and 45 °C with 1C rate, the pouch batteries prepared by 1 wt.% Li7La3Zr2O12 coated Ni-rich LiNi0.87Co0.05Mn0.05Al0.03O2 cathode respectively deliver the discharge capacity retention of 89.9% and 87.7%, superior than those (85.3% and 80.9) of the pristine cathode. Besides, the cathode after the 1 wt.% Li7La3Zr2O12 coating also demonstrates the much promotion on safety performance in comparison with the pristine cathode, such as the Bar impact and Nail penetration tests. [Display omit