Preparation method of layered lithium (Li)-rich manganese (Mn)-based anode material having multiple core-shell structures

Abstract

The invention discloses a preparation method of a layered lithium (Li)-rich manganese (Mn)-based anode material having multiple core-shell structures. The layered (1-t)LiNixCoyMn1-x-yO2@tLi2MnO3 having the multiple core-shell structures is prepared by taking LiNixCoyMn1-x-yO2 (the x is greater than or equal to 0 while the y is less than or equal to 1) as cores and Li2MnO3 with the concentration in gradient change as shells. According to the method, the core-shell structures are applied into the lithium (Li)-rich layered material, namely, the concept of the multiple core-shell structures is put forward, so that the defects reported in the literature that the simple core-shell structure material has poor performance and the concentration gradient material is complicated to operate and difficult to realize are overcome. In the method, the core-shell concentrations are in antigradient change according to a certain arithmetic progression, namely, from the cores to the outer shells, the concentrations of the core materials are in gradually-decreased arithmetic progression distribution while the concentrations of the shell material are in gradually-increased arithmetic progression distribution. During the design, the equal concentration of transition metal ions in every layer is ensured, so that the interfacial resistance of the materials is reduced as far as possible. As a result, the material performance is improved.

Description

technical field [0001] The invention relates to a preparation method of a layered lithium-rich manganese-based positive electrode material with multiple core-shell structures. Background technique [0002] Since it can exhibit unusual electrochemical properties, such as high specific capacity (discharge specific capacity exceeding 230mAh / g, up to 300mAh / g), high specific power (up to 300Wh / kg), and a new electrochemical charge-discharge mechanism, the layer lithium-like material Li 1+X+ m 1-x o 2 (M is one or more transition metal elements) has become one of the research hotspots in the field of cathode materials for lithium-ion batteries worldwide, making it the most likely candidate for cathode materials for next-generation high-performance lithium-ion battery technology . After nearly 20 years of research, researchers have proposed many improvement measures (such as bulk phase doping, surface coating, etc.) to address the defects of this type of material, which has gr...

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Problems solved by technology

However, the first core-shell structure material proposed by Sun is simple to prepare and has strong controllability, but its performance is worse than the second core-shell structure material proposed by them; while the second core-shell structure material has excellent performance, but it is difficult to prepare. Poor controllability, not easy for industrial production, resulting in poor product consistency