Enhanced performance of a Ni-rich LiNi0.8Co0.1Mn0.1O2 cathode material formed through Taylor flow synthesis and surface modification with Li2MoO4

Abstract

We use a novel continuous Taylor flow reactor to prepare a high-energy–density, highly stable Ni-rich LiNi0.8Co0.1Mn0.1O2 cathode material for potential use in Li-ion batteries. The secondary particles of as-prepared LiNi0.8Co0.1Mn0.1O2 possess an elliptical morphology; the primary particles have a nanosheet structure on the preferred {010} plane. Furthermore, we modify the as-prepared LiNi0.8Co0.1Mn0.1O2 cathode material via surface coating with Li2MoO4. Because of the pillar effect of the ionic conductor Li2MoO4, the modified LiNi0.8Co0.1Mn0.1O2 cathode material exhibits a lower degree of Li+/Ni2+ cation mixing, high structural stability and enhanced electrochemical performance at 2.5–4.3 and 2.5–4.5 V at 25 °C and 55 °C respectively. Our as-prepared and Li2MoO4-modified LiNi0.8Co0.1Mn0.1O2 cathode materials deliver discharge capacities of 199.62 and 203.87 mA h g−1, respectively, at a rate of 0.1C. The optimal 2 wt% Li2MoO4–coated LiNi0.8Co0.1Mn0.1O2 cathode achieves a capacity retention of 93.99% at 1C/1C for 100 cycles; the capacity retention of the as-prepared LiNi0.8Co0.1Mn0.1O2 is 85.48% higher than that of a commercial LiNi0.8Co0.1Mn0.1O2 product (only 68.70%). We use in situ XRD and in operando microcalorimetry to measure the volumes, changes in lattice parameters, and thermal stabilities of our prepared and modified LiNi0.8Co0.1Mn0.1O2 products.