(1. 中南大學(xué) 冶金與環(huán)境學(xué)院，長(zhǎng)沙 410083；
2. 中南大學(xué) 粉末冶金國(guó)家重點(diǎn)實(shí)驗(yàn)室，長(zhǎng)沙 410083)
摘 要: 針對(duì)本征低的電子導(dǎo)電率和鋰離子遷移速率導(dǎo)致LiFePO4較差的電化學(xué)性能，以石墨烯作為模板，采用一步溶劑熱法制備梭形結(jié)構(gòu)的LiFePO4/石墨烯(LFP/G)復(fù)合正極材料；采用XRD和SEM等表征復(fù)合正極材料的物相結(jié)構(gòu)和微觀形貌，微米級(jí)梭型LiFePO4顆粒是由平均厚度約為55 nm的納米薄片堆疊而成。電化學(xué)性能研究結(jié)果表明：在0.1C倍率下，LFP/G復(fù)合正極材料的初始可逆比容量可達(dá)153.2 mA？h/g，高于相同條件下LiFePO4的；在10C倍率下充放電時(shí)，LFP/G表現(xiàn)出高達(dá)85.9 mA？h/g的可逆比容量，遠(yuǎn)高于LiFePO4的可逆比容量(56.3mA？h/g)，展現(xiàn)出明顯增強(qiáng)的電化學(xué)倍率性能。
關(guān)鍵字: 磷酸鐵鋰納米片；石墨烯復(fù)合材料；梭型結(jié)構(gòu)；正極材料；鋰離子電池
（1. School of Metallurgy and Environment, Central South University, Changsha 410083, China;
2. State Key Laboratory for Powder Metallurgy, Central South University, Changsha 410083, China）
Abstract:Aiming at the intrinsic shortcomings of LiFePO4, a spindle-like LiFePO4/graphene (LFP/G) composite cathode material was conveniently prepared by a one-step solvothermal method using graphene as a template. The as-obtained material was characterized by XRD, SEM and other methods. The results show that the micron-sized spindle-like LiFePO4 particles are stacked by nano-sheets with average thickness of about 55 nm. Electrochemical performance study results show that the LFP/G composite cathode material exhibits an initial reversible specific capacity of 153.2 mA？h/g at 0.1C rate, which is higher than that of LiFePO4 under the same conditions; when charged and discharged at 10C rate, LFP/G exhibits a reversible specific capacity of up to 85.9 mA？h/g, which is much higher than that of LiFePO4 (56.3 mA？h/g), exhibiting significantly enhanced electrochemical rate performance.
Key words: LiFePO4nanoflakes; graphene composite; spindle-shaped structure; cathode material; lithium-ion batteries
