CAJ | 학술논문

分别以Fe(NO_3)_3·9H_2O和FeSO_4·7H_2O为铁源,采用均相沉淀法和氧化-液相沉淀法制备了两种不同形貌的FePO_4粉体,再以FePO_4为前驱体,与LiOH·H_2O、蔗糖混合,采用碳热还原法合成了LiFePO_4正电极材料.用XRD和SEM对所制备的FePO_4粉体进行结构和表面形貌表征,测试了LiFePO_4样品的充放电性能.XRD和SEM测定结果表明,采用均相沉淀法制备的FePO_4为六方晶系纯相,颗粒形貌为圆片状,颗粒大小均匀;而液相氧化法制备的FePO_4也为六方晶系纯相,但颗粒形貌无规则.由圆片状FePO_4和无规则FePO_4所合成的LiFePO_4的颗粒形貌与其前驱体相同.充放电测试表明在0.5C下圆片状LiFePO_4的首次放电比容量为140 mAh/g,无规则LiFePO_4的首次放电比容量为89 mAh/g.经过50次循环后,前者的放电比容量仅下降1.43%,后者基本不变.
분별이Fe(NO_3)_3·9H_2O화FeSO_4·7H_2O위철원,채용균상침정법화양화-액상침정법제비료량충불동형모적FePO_4분체,재이FePO_4위전구체,여LiOH·H_2O、자당혼합,채용탄열환원법합성료LiFePO_4정전겁재료.용XRD화SEM대소제비적FePO_4분체진행결구화표면형모표정,측시료LiFePO_4양품적충방전성능.XRD화SEM측정결과표명,채용균상침정법제비적FePO_4위륙방정계순상,과립형모위원편상,과립대소균균;이액상양화법제비적FePO_4야위륙방정계순상,단과립형모무규칙.유원편상FePO_4화무규칙FePO_4소합성적LiFePO_4적과립형모여기전구체상동.충방전측시표명재0.5C하원편상LiFePO_4적수차방전비용량위140 mAh/g,무규칙LiFePO_4적수차방전비용량위89 mAh/g.경과50차순배후,전자적방전비용량부하강1.43%,후자기본불변.
Two kinds of FePO_4 powders with morphologies were prepared with Fe (NO_3)_3· 9H_3O and FeSO_4· 7H_2O as iron source by using homogeneous precipitation method and oxidize-liquid-de-posited method respectively. The prepared FePO_4 then mixed with LiOH· H_2O and sugar to synthe-size cathode material LiFePO_4 by carbothermal reduction method. The structure and morphology of prepared FePO_4 and LiFePO_4 were characterized by X-ray diffraction (XRD), scanning electron mi-croscopy(SEM). The charge-recharge performance of LiFePO_4 was also measured. The results show that FePO_4 particles prepared by homogeneous precipitation method are wafer-like in morphology, while the FePO_4 particles prepared by oxidize-liquid-deposited method are shapeless. Both of them are hexagonal structure. Testing of the electrochemical performance shows that the specific discharge capacities of LiFePO_4 of wafer-like and shapeless are 140 mAh·g~(-1) and 89 mAh ·g~(-1) respectively at the 0. 5C rate. The discharge capacity decreased 1.43% merely for the former and no change for the later after 50 cycles.