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Enhanced Li+diffusion kinetics and energy storage are obtained due to the charge polarization for SiGe heterostructure, which renders superior rate capability and excellent cycling stability.

P2-Na0.67Ni0.33Mn0.37Ti0.3O1.9F0.1exhibits excellent structure stability in high voltage range of 2.0–4.4 V due to the suppressed P2-O2 phase transition and Na+/vacancy ordering, resulting in capacity retention of 77.2% after 300 cycles at 2 C.

LiNi0.915Co0.075Al0.01O2(NCA) with Zr(OH)4coating is demonstrated as high performance cathode material for lithium ion batteries (LIBs). The coated materials are synthesized via a simple dry coating method of NCA with Zr(OH)4powders, and then characterized with scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). Experimental results show that amorphous Zr(OH)4powders have been successfully coated on the surface of spherical NCA particles, exhibiting improved electrochemical performance. 0.50wt% Zr(OH)4coated NCA delivers a capacity of 197.6mAh/g at the first cycle and 154.3mAh/g after 100 cycles with a capacity retention of 78.1% at 1 C rate. In comparison, the pure NCA shows a capacity of 194.6mAh/g at the first cycle and 142.5mAh/g after 100 cycles with a capacity retention of 73.2% at 1 C rate. Electrochemical impedance spectroscopy (EIS) results show that the coated material exhibits a lower resistance, indicating that the coating layer can efficiently suppress transition metals dissolution and decrease the side reactions at the surface between the electrode and electrolyte. Therefore, surface coating with amorphous Zr(OH)4is a simple and useful method to enhance the electrochemical performance of NCA-based materials for the cathode of LIBs.

The P2-Na0.67Ni0.28Zn0.05Mn0.62Ti0.05O2cathode achieves long-term cycle stability owing to the synergistic action of Zn/Ti co-doping and introduced LiPO2F2film-forming electrolyte additive.