Grafting Benzenediazonium Tetrafluoroborate onto LiNixCoyMnzO2 Materials Achieves Subzero-Temperature High-Capacity Lithium-Ion Storage via a Diazonium Soft-Chemistry Method

Subzero-temperature Li-ion batteries (LIBs) are highly important for specific energy storage applications. Although the nickel-rich layered lithium transition metal oxides(LiNixCoyMnzO2) (LNCM) (x > 0.5, x + y +z = 1) are promising cathode materials for LIBs, their very slow Li-ion diffusion is a main hurdle on the way to achieve high-performance subzero-temperature LIBs. Here, a class of low-temperature organic/inorganic hybrid cathode materials for LIBs, prepared by grafting a conducting polymer coating on the surface of 3 mu m sized LiNi0.6Co0.2Mn0.2O2 (LNCM-3) material particles via a greener diazonium soft-chemistry method is reported. Specifically, LNCM-3 particles are uniformly coated with a thin polyphenylene film via the spontaneous reaction between LNCM-3 and C6H5N2+BF4-. Compared with the uncoated one, the polyphenylene-coated LNCM-3 (polyphenylene/LNCM-3) has shown much improved low-temperature discharge capacity (approximate to 148 mAh g(-1) at 0.1 C, -20 degrees C), outstanding rate capability (approximate to 105 mAh g(-1) at 1 C, -20 degrees C), and superior low-temperature long-term cycling stability (capacity retention is up to 90% at 0.5 C over 1150 cycles). The low-temperature performance of polyphenylene/LNCM-3 is the best among the reported state-of-the art cathode materials for LIBs. The present strategy opens up a new avenue to construct advanced cathode materials for wider range applications.