(中南大學(xué) 冶金科學(xué)與工程學(xué)院，長(zhǎng)沙 410083)
摘 要: 以FeSO4·7H2O，H3PO4，H2O2和NH3·H2O為原料合成FePO4·xH2O前驅(qū)體，考察制備過程溶液pH值對(duì)合成FePO4·xH2O前驅(qū)體性能的影響；將Li2CO3，FePO4·xH2O和乙炔黑球磨混合，通過低溫固相反應(yīng)合成LiFePO4。用X射線衍射和掃描電鏡對(duì)FePO4·xH2O和LiFePO4進(jìn)行結(jié)構(gòu)和表面形貌表征，研究不同pH值條件下合成的FePO4·xH2O前驅(qū)體為原料對(duì)制備的LiFePO4電化學(xué)性能的影響。結(jié)果表明：溶液pH值1.5時(shí)制備的FePO4·xH2O中含有少量Fe(PO4)2(OH)2雜質(zhì)，當(dāng)pH分別為2、3、4和5時(shí)，合成的FePO4·xH2O均為純相。pH值為2左右合成的FePO4·xH2O前驅(qū)體制備出的LiFePO4具有良好的電化學(xué)性能；其振實(shí)密度達(dá)
關(guān)鍵字: 鋰離子電池；LiFePO4；PO4•xH2O；電化學(xué)性能
（School of Metallurgical Science and Engineering, Central South University, Changsha 410083, China）
Abstract:FePO4•xH2O precursor was synthesized from FeSO4•7H2O, H3PO4, H2O2 and NH3•H2O under various pH value. LiFePO4 cathode material was then synthesized by low temperature sintering of the homogeneous mixture of Li2CO3，acetylene black and FePO4•xH2O. The effect of the solution pH on the performance of FePO4•xH2O was characterized. The structures of FePO4•xH2O and LiFePO4 were characterized by XRD and SEM. The effect of the solution pH on the electrochemical performance of LiFePO4 was discussed. The results show that no impurities exist in the FePO4•xH2O synthesized at pH value ranging in 2 and 5. LiFePO4 made from FePO4•xH2O precursor synthesized under the condition that the solution pH is about 2 show excellent electrochemical performance, and the tap density reaches 1.11 g/cm3.
Key words: lithium ion batteries; LiFePO4; FePO4•xH2O; electrochemical performance
