Search

[Display omitted] Li-rich Mn-based oxides (LRMOs) are considered as one of the most-promising cathode materials for next generation Li-ion batteries (LIBs) because of their high energy density. Nevertheless, the intrinsic shortcomings, such as the low first coulomb efficiency, severe capacity/voltage fade, and poor rate performance seriously limit its commercial application in the future. In this work, we construct successfully g-C 3 N 4 coating layer to modify Li 1.2 Mn 0.54 Ni 0.13 Co 0.13 O 2 (LMNC) via a facile solution. The g-C 3 N 4 layer can alleviate the side-reaction between electrolyte and LMNC materials, and improve electronic conduction of LMNC. In addition, the g-C 3 N 4 layer can suppress the collapse of structure and improve cyclic stability of LMNC materials. Consequently, g-C 3 N 4 (4 wt%)-coated LMNC sample shows the highest initial coulomb efficiency (78.5%), the highest capacity retention ratio (78.8%) and the slightest voltage decay (0.48 V) after 300 loops. Besides, it also can provide high reversible capacity of about 300 and 93 mAh g−1 at 0.1 and 10C, respectively. This work proposes a novel approach to achieve next-generation high-energy density cathode materials, and g-C 3 N 4 (4 wt%)-coated LMNC shows an enormous potential as the cathode materials for next generation LIBs with excellent performance. [ABSTRACT FROM AUTHOR]

The NASICON structure of Na 3 V 2 (PO 4) 2 F 3 (NVPF) separates the valence electrons between the polyanion group and V and regulates the redox coupling energy. As a result, NVPF exhibits a high operating voltage in sodium-ion batteries. However, NVPF cathode material has poor specific capacity and low-rate performance. It is necessary to improve the electrochemical performance by increasing the electronic conductivity and accelerating the ion diffusion rate. Through morphology control, more active sites and ion channels can be provided to enhance rate performance and cycle stability. However, there are few reviews on how to control the morphology of NVPF. Therefore, this paper starts with the factors affecting the morphology of NVPF. The effects of pH value, surfactant, and external additives on its morphology were systematically summarized. On this basis, reasonable strategies, including morphology design, preparation method, structure control, surface modification, and defect engineering, are summarized. This paper provides theoretical support for the development of high-voltage NVPF. It provides inspiration for creating NVPF cathode materials with high specific capacity and high cycle performance. • The effects of various factors on the morphology of Na 3 V 2 (PO 4) 2 F 3 were systematically summarized. • The electrochemical properties of Na 3 V 2 (PO 4) 2 F 3 coated with different carbon sources were summarized. • The low-pressure platform caused by fluorine loss and its fluorine supplement measures are explained. • The effects of binders and electrolyte additives on Na 3 V 2 (PO 4) 2 F 3. [ABSTRACT FROM AUTHOR]