Nitrogen-doped carbon-coated manganese monoxide composite material with one-dimensional porous core-shell structure and preparation method of nitrogen-doped carbon-coated manganese monoxide composite material

Abstract

The invention relates to a nitrogen-doped carbon-coated manganese monoxide composite material with a one-dimensional porous core-shell structure and a preparation method of the nitrogen-doped carbon-coated manganese monoxide composite material. The composite material is doped with nitrogen, is in a one-dimensional porous carbon-coated manganese monoxide core-shell structure; manganese monoxide is in a nano rodlike structure; and an outer layer of a manganese monoxide nanorod is coated with an amorphous carbon layer. The nitrogen-doped carbon-coated manganese monoxide composite material is obtained by an in-situ polymer coating method accompanied by burning. The preparation method of the composite material is simple and novel, and high in adjustability; and meanwhile, nitrogen-doped carbon can store lithium ions. Due to the ingenious design, the specific capacity of the composite material exceeds the theoretical specific capacity of the manganese monoxide; furthermore, according to the composite material, the problems of low capacity and fast attenuation caused by poor conductivity and high volumetric strain of a pure manganese monoxide material are solved; and the composite material has excellent electrochemical properties, cycle lifetime and structural stability.

Description

technical field [0001] The invention belongs to new energy nanometer energy storage materials, and specifically relates to a one-dimensional porous core-shell structure nitrogen-doped carbon-coated manganese monoxide composite material, a preparation method and an application thereof. Background technique [0002] The widespread use of energy storage devices such as portable electronic devices, electric vehicles, and grid energy storage systems has greatly promoted the rapid development of lithium-ion batteries, which are outstanding representatives of new energy storage. As a negative electrode material for traditional commercial lithium-ion batteries, graphite has greatly limited the further development of lithium-ion batteries due to its low theoretical capacity (372mAh / g) and low cycle life. Therefore, the development of a lithium-ion battery anode material with high specific capacity and excellent cycle performance is of great significance for expanding the application ...

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Problems solved by technology

However, in practical applications, there are mainly two problems: on the one hand, the low electronic conductivity of manganese monoxide leads to poor rate performance and low reversible capacity; on the other hand, the volume strain of manganese monoxide is large during the electrochemical cycle. , causing material agglomeration and pulverization, and rapid capacity decay

For example, Guo et al. of Shandong University (GuoS, LuG, QiuS, et al. Carbon-coatedMnOmicroparticleporous nanocompositesservingasanodematerialswithinhancedelectrochemicalperformances[J]. NanoEnergy, 2014, 9: 41-49.) prepared carbon-coated manganese monoxide porous microsphere composites by hydrothermal method, Compared with the pure sample, the obtained composite material has excellent performance. At 100mA / g, the first-cycle capacity is 590.6mAh / g. After 100 cycles, the capacity is still 525.4mAh / g. When the current density is 800mA / g, the capacity can reach 238.2mAh / g; Sun Yat-sen University Liu et al. (LiuH, LiZ, LiangY, et al. Facile synthesis of MnOmulti-corenitrogen-doped carbonshell nanoparticles for high performancelithium-ionbatteryanodes[J]. Carbon, 2015,84:419-425.) Prepared a carbon-coated multi-core structure The electrochemical performance of the manganese monoxide nanosphere composite material has been significantly improved. At 100mA / g, the capacity of the first cycle is 799mAh / g, which drops to 608mAh / g after 5 cycles, and the capacity is still 578mAh / g after 60 cycles. , at 1000mA / g, the capacity can reach 254mAh / g; although some progress has been made in the research on the modification of manganese monoxide electrode materials, at present, most of the documents and patents including the above-mentioned documents prepare manganese monoxide composite materials. They are all relatively complicated and costly. At the same time, at a high current density (greater than 500mA / g), the cycle life is still difficult to exceed 500 cycles or higher, and the specific capacity is still relatively low.

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