A kind of preparation method of nanoscale tinb2o7 with porous structure

Abstract

The invention discloses a preparation method of porous nanoscale TiNb2O7. The preparation method of the porous nanoscale TiNb2O7 comprises the following specific steps: (a) adding a titanium source and a niobium source in the molar ratio of 1 to 2 into a dispersant, dispersing and mixing; and (b) pouring the mixture obtained in the step (a) into a porcelain boat, roasting at the temperature of 700-900 DEG C, preserving heat for 3-6 hours, and cooling the product of reaction to room temperature to obtain the porous nanoscale TiNb2O7, wherein the temperature is increased at a speed of 1-5 DEG C per minute. The preparation method of the porous nanoscale TiNb2O7 is easy to operate, and the obtained porous nanoscale TiNb2O7 has small particle size, uniform particle size distribution and good stability and consistency. Due to the abundant pore passages of the porous nanoscale TiNb2O7, an active material can be fully soaked by an electrolyte, and due to the nanoscale particles of the porous nanoscale TiNb2O7, the transmission distance between lithium ions and electrons in the charging and discharging process can be shortened effectively, and the high-current charging and discharging capability of the TiNb2O7 can be improved. The porous nanoscale TiNb2O7 has excellent electrochemical properties and broad application prospects.

Description

technical field [0001] The invention relates to the field of preparation of electrochemical materials and energy, in particular to nanoscale TiNb with a porous structure for lithium-ion battery anode materials 2 o 7 method of preparation. Background technique [0002] TiNb using a layered monoclinic structure was proposed by the Goodenough group 2 o 7 It is a new type of negative electrode material for lithium-ion batteries, with a theoretical capacity of 387.6mAhg -1 , there is an electron transfer reaction (Ti 4+ / Ti 3+ ,Nb 5+ / Nb 3+ ), is currently commonly used Li 4 Ti 5 o 12 material (its theoretical capacity is only 175mAhg -1 ), and the charge-discharge potential is not much different, which can effectively avoid the formation of solid electrolyte interfacial film (SEI), ensure the safety of the electrode and a long cycle life, however, TiNb 2 o 7 The intrinsic electron conductivity and ion conductivity of the material are low, resulting in rapid capacity...

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Problems solved by technology

Among them, the traditional solid-phase method has the characteristics of simple raw materials, simple technical process, and convenient operation, but the size of the product is large, and the distribution is uneven, and the energy consumption is relatively large due to the long calcination time at high temperature. The general electrochemical performance of the product is not ideal; 2 o 7 ) published a high-temperature solid-phase synthesis of TiNb 2 o 7 The method requires a temperature as high as 1350°C and a reaction time of 24h. The average size of the obtained product is 20μm, and the discharge capacity is 281mAhg at 0.1C. -1 , the Coulombic efficiency is only 93%; the sol-gel method needs to add organic chemicals, which leads to an increase in its cost, and the gelation into powder is a violent expansion process, and the utilization rate of the reactor is low; HanJiantao et al. In 2029 (NewAnodeFrameworkforRechargeableLithiumBatteries), the preparation of TiNb by sol-gel method was published. 2 o 7 The method requires raw materials such as niobium pentoxide, hydrofluoric acid solution, titanium isopropoxide, ammonia water, citric acid, etc., and is finally calcined at 900-1350°C to obtain the final product, but electrochemical tests show that in At 0.1C, the obtained TiNb prepared by this method 2 o 7 After 10 cycles, the capacity is only 200mAhg -1 , not suitable for industrial application; the soft and hard template method needs to add additional templates, which leads to an increase in cost and also makes the operation process too cumbersome. FeiLing, GuoBingkun, ChangshinJo et al. prepared nano Grade TiNb 2 o 7 , whose work was published in Nanoscale5(2013) 11102~11107 (SBA-15confinedsynthesisofTiNb 2 o 7 nanoparticlesforlithium-ionbatteries), Energy&EnvironmentalScience7 (2014) 2220~2226 (Along-lifelithium-ionbatterywithhighlyporousTiNb 2 o 7 anodeforlarge-scaleelectricalenergystorage), ChemistryofMaterials26 (2014) 3508~3514 (BlockCopolymerDirectedOrderedMesostructuredTiNb 2 o 7 MultimetallicOxideConstructedofNanocrystalsasHighPowerLi-ionBatteryAnodes), because the prepared material is nanoscale and has a porous structure, its electrochemical properties have been greatly improved, but the above-mentioned preparation process requires the use of templates, which increases the production cost and is also the preparation of The process is too cumbersome

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