A nickel-rich oxide, Li(Ni0.90Co0.06Mn0.04)0.995Al0.005 O2, with a dual conductive coating

Abstract

Nickel (Ni)-rich layered oxides have high specific capacities and are inexpensive, but their synthesis and electrochemical performance continue to present difficulties. In this study, we investigated the effect of a dual conductive compound of dot-like Nb12WO33 and film-like lithium boron oxide (Li-B-O; applied using a simple dry-coating method) on the Ni-rich oxide layer in Li batteries. The film-like Li-B-O homogeneous coating segregated the cathode from the electrolyte, which improved the initial efficiency and cycle stability, and the dot-like Nb12WO33 provided a fast Li-ion transition channel, which improved the rate performance of the Ni-rich oxide layer. The modified cathode with dual conductive coating exhibited significantly improved electrochemical performance. Its discharge capacity was 225.6 mAh g−1, with high initial efficiency of 92.73% in the voltage range of 3.0–4.3 V at 0.1 C, whereas that of the uncoated sample was 219.4 mAh g−1, with an initial efficiency of 90.4%. The modified cathode had a discharge capacity of 179.1 mAh g−1 at 5 C, compared with that of 161.1 mAh g−1 for the uncoated sample; the capacity retention of the coated sample was 92.84% at 0.5 C after 50 cycles at 25 ℃, whereas that of the uncoated sample was only 81.41%. A similar strategy could be utilized to enhance the performance of other cathode materials.