Preparation method for metal-doped lithium/carbon manganese phosphate composite from manganese phosphate

Abstract

The invention discloses a preparation method for a metal-doped lithium / carbon manganese phosphate (LiMXMn1-XPO4 / C) composite from manganese phosphate. The method comprises the following steps: preparing active manganese phosphate materials (MnPO4) with different shapes by using a precipitation or sol-gel method; then subjecting prepared manganese phosphate, a lithium source and a metal-doped elemental compound to ball milling for 20 to 50 h and mixing with alcohol used as a dispersant; carrying out vacuum drying and crushing to obtain a crushed substance; placing the crushed substance in a stainless steel container, heating the crushed substance to a temperature of 450 to 800 DEG C in a furnace protected by an inert atmosphere and maintaining the temperature for 2 to 12 h; and rapidly placing the substance to a liquid coolant under the conditions of a high temperature and air isolation and carrying out rapid cooling so as to obtain the LiMXMn1-XPO4 / C composite. The method provided by the invention has shortened process flow, can maintain particle activity in a high temperature, effectively gives rise to structural dislocation, improves the ionic migration rate and electronic conductivity of the composite and is suitable for large-scale industrial production.

Description

technical field [0001] The invention relates to the technical field of energy materials, and discloses a method for preparing metal-doped lithium manganese phosphate / carbon LiM with manganese phosphate X mn 1-X PO 4 / C composite material method, especially one adopts precipitation method and sol-gel method to control crystallization to prepare manganese phosphate precursor primary ion and ion activity, ball mill mixing, controlled calcination, and rapid cooling method to prepare metal-doped manganese phosphate Lithium / carbon LiM X mn 1-X PO 4 / C composite method. Background technique [0002] The development of lithium-ion secondary batteries has a history of 20 years. So far, the transition metal oxides that can form intercalated compounds with lithium are the most researched. In the past two decades, people have found six practical positive electrode active materials through the research on lithium-ion secondary battery electrode materials: lithium cobaltate (LiCoO ...

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Problems solved by technology

However, since LiMnPO 4 The material is extremely poorly conductive and is considered an insulator, leading to the synthesis of LiMnPO capable of reversible charge and discharge 4 Very difficult, which limits its development and application

In the public documents of many patent applications for lithium manganese iron phosphate / carbon composite materials, the electrochemical performance of the material is improved by carbon coating and metal doping, and a relatively ideal capacity is obtained, but the preparation methods are relatively cumbersome, making it The difficulty of industrialization is high, and it increases the cost and it is difficult to guarantee the batch stability of the product, making it more difficult to improve the yield in the battery factory and solve the problem

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