(中南大學 冶金科學與工程學院，長沙 410083)
摘 要: 采用固相反應法合成摻碳鋰離子電池正極材料LiMnPO4。利用XRD、SEM和充放電測試表征LiMnPO4的結構、形貌與充放電性能，并研究LiMnPO4電極的交流阻抗和鋰離子的擴散行為。研究表明：適當提高合成溫度與延長反應時間有利于促進晶體結構的完整，提高材料的放電平臺和放電容量，改善電極反應表面電荷傳遞和材料中的鋰離子擴散特性。在600 ℃燒結時間為24 h的條件下可合成出一次顆粒大小為0.1~0.3 μm的純相LiMnPO4, 樣品容量達到95 mA∙h/g，充電態(tài)下鋰離子的擴散速度為5.65×10−13 cm2/s。
關鍵字: LiMnPO4；鋰離子電池；橄欖石；正極材料
（School of Metallurgical Science and Engineering, Central South University, Changsha 410083, China）
Abstract:Carbon-containing LiMnPO4 was synthesized by solid-state reaction. The structure, surface morphology and charge-discharge performance of LiMnPO4 were characterized by X-ray diffractometry, scanning electron microscopy and electrochemical measurement respectively. The AC impedance and diffusion coefficient of lithium ion for LiMnPO4 were also studied. The results show that proper increase of temperature and sintering time improve the crystal structure, increase the discharge voltage plateau and capacity, and enhance the transfer of surface electrons and lithium ion diffusion. Good samples with pure phase and primary particle size of 0.1~0.3 μm can be prepared at 600 ℃ for 24 h. These samples possess capacity of 95 mA∙h/g and lithium ion diffusion coefficient of 5.65×10−13 cm2/s.
Key words: LiMnPO4; lithium ion batteries; olivine; cathode materials
