Carbon-coated lithium iron phosphate digestion device, digestion method and detection method

Abstract

The invention provides a carbon-coated lithium iron phosphate digestion device, a digestion method and a detection method. The device comprises a digestion container and a heater, the digestion container comprises a digestion pipe, a digestion cover matched with the digestion pipe, two through holes formed in the top of the digestion cover and sealing plugs matched with the through holes, and at least one digestion pipe containing hole is formed in the heater and used for containing the digestion pipe. According to the device, inert gas is introduced before digestion, the inert atmosphere in the digestion process is guaranteed, and then the proportion of ferrous iron to ferric iron is protected against damage; the heater can complete digestion of a plurality of samples at a time, and the digestion efficiency is high. The digestion method provided by the invention is simple to operate, and the components in the obtained digestion solution are equivalent to the components in the originalcompound; according to the carbon-coated lithium iron phosphate detection method provided by the invention, the prepared digestion solution is used as a detection solution, and the accurate content of iron elements with different valence states in the carbon-coated lithium iron phosphate material can be accurately tested.

Description

technical field [0001] The invention relates to the technical field of analysis and detection, in particular to a carbon-coated lithium iron phosphate digestion device, a carbon-coated lithium iron phosphate digestion method, and a method for detecting ferric iron content in carbon-coated lithium iron phosphate. Background technique [0002] Almost all lithium iron phosphates currently on the market are designed with a carbon-coated process. Due to the limitations of different process defects, there are traces of ferric ions in carbon-coated lithium iron phosphate materials. The existence of trivalent iron element is extremely unfavorable to lithium iron phosphate materials. It will make LiFePO 4 The self-discharge of the positive electrode material increases, and the specific capacity decreases. At the same time, the dissolution of iron and the precipitation on the carbon negative electrode will occur during the cycle, resulting in the deterioration of its cycle performan...

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Problems solved by technology

Secondly, due to the limitation of its own test accuracy, it is difficult to separate trace amounts of ferric ions by fluorescence spectroscopy.

(Patent CN201410223124-a method for fluorescence detection of ferric ions); (2) XPS, EDS, XNES, A-3 Mössbauer method and other material characterization methods are feasible in principle, and can be directly scanned and tested without destroying the digested sample, but Quantitative analysis has a large error, the analysis method is complicated, and the analysis cost is high for the factory, so it is difficult to implement; (3) The microwave digestion method is complicated, cumbersome and inconvenient. The volatilization of a large amount of acid mist in the environment will inevitably carry some iron sources, resulting in a decrease in the content of iron elements

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