A design strategy of large grain lithium-rich layered oxides for lithium-ion batteries cathode

• Ultrasound-assisted mixing lithium was used to synthesize Lithium-rich layered oxides.
• Lithium-rich layered oxides composed of large grain had high capacity and high cycling stability.
• This unique large grain overcomes stress-induced structural collapse caused by Li-ion insertion/extraction and reduces dissolution of Mn ions.
• A new strategy of large grain could be employed to synthesize the other complex architectures for various applications.

Li-rich materials are considered the most promising for Li-ion battery cathodes, as high capacity can be achieved. However, poor cycling stability is a critical drawback that leads to poor capacity retention. Here a strategy is used to synthesize a large-grain lithium-rich layered oxides to overcome this difficulty without sacrificing rate capability. This material is designed with micron scale grain with a width of about 300 nm and length of 1–3 μm. This unique structure has a better ability to overcome stress-induced structural collapse caused by Li-ion insertion/extraction and reduce the dissolution of Mn ions, which enable a reversible and stable capacity. As a result, this cathode material delivered a highest discharge capacity of around 308 mAh g−1 at a current density of 30 mA g−1 with retention of 88.3% (according to the highest discharge capacity) after 100 cycles, 190 mAh g−1 at a current density of 300 mA g−1 and almost no capacity fading after 100 cycles. Therefore, Lithium-rich material of large-grain structure is a promising cathode candidate in Lithium-ion batteries with high capacity and high cycle stability for application. This strategy of large grain may furthermore open the door to synthesize the other complex architectures for various applications.

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