燃烧法制备LiFePO4及其燃烧机制

许多合成磷酸铁锂(LFP)的传统方法具有反应时间长或者Fe²⁺易氧化的缺点.使用硫酸亚铁、磷酸氢二铵和硝酸锂为主要原料,通过燃烧法制备LFP,由XRD和TG-DSC表征所得样品.结果表明,该燃烧法可以在600 ℃短时间内合成较纯的LFP,并且不需要通入保护气体.对燃烧机制的研究表明,从120~290 ℃,干凝胶的燃烧导致有机柠檬酸的自蔓延燃烧反应,同时引入的碳防止Fe²⁺的氧化,并且当φ=n(CA)/n(LFP)=2时,是合成LFP材料柠檬酸的最佳用量.

Combustion Method to Synthesize LiFePO4 and Combustion Mechanism

Many traditional methods used to synthesize LiFePO₄ (LFP for short) have the disadvantages of long reaction time or unavoidable oxidation of Fe²⁺.In this work,the combustion method was developed to facilely synthesize LFP by using ferrous sulfate,diammonium hydrogen phosphate and lithium nitrate as main raw materials.The synthesized LFP was characterized by XRD and TG-DSC.The results showed that the combustion method could facilely synthesize purer LFP at 600 ℃ in a short period without the protection of inert gas.The studies on combustion mechanism indicated that from 120 ℃ to 290 ℃ the organic citric acid in the dry gel was combusted which could lead to a self-propagating combustion reaction and bring in carbon preventing the oxidation of Fe²⁺ simultaneously.And φ=n(CA)/n(LFP)=2 is the best amount of citric acid to synthesize LFP materials.