Improved electrochemical properties of LiFePO4/graphene cathode nanocomposite prepared by one-step hydrothermal method

• Published in: Journal of alloys and compounds Vol. 627; pp. 146 - 152
• Main Authors: Fathollahi, Fatemeh, Javanbakht, Mehran, Omidvar, Hamid, Ghaemi, Mehdi
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 05.04.2015
• Subjects: Graphene; Hydrothermal synthesis; LiFePO4; Lithium ion battery; Nanocomposite; Lithium ion battery; Nanocomposite; Hydrothermal synthesis; Graphene; LiFePO4
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/j.jallcom.2014.12.025

•This method was used for synthesized LiFePO4/graphene (LFP/G) active material.•LFP/G composite was prepared in a template-free method using graphene nano-sheets.•This work provides a simple economic strategy for the preparation of LFP cathode. LiFePO4/graphene active material (LFP/G) was successfully synthesized via a simple, low raw material cost and environment friendly hydrothermal method at 170°C. LFP/G composite was prepared in a template-free method using graphene nano-sheets as a conductive additive (3.0wt.%) without any carbon coating. Results indicated the presence of LFP crystallites of the olivine phase, which are randomly anchored on the surface of graphene. Electrochemical characteristics of the LFP/G modified electrode show well-defined peaks, smaller peak potential separation and higher cycling stability compared to those of the pristine LFP obtained in the absence of graphene. LFP/G delivered an initial discharge capacity of 157mAhg−1 at 0.2C and 114mAhg−1 at 5C and the values were compared to those of LFP (the capacities reach up to 120mAhg−1 at 0.1C and 50mAhg−1 at 5C). The electrochemical enhancement of LFP/G could be mainly ascribed to synergetic effects of bridging graphene nanosheets and creating an interconnected conducting network of cross-linking between neighboring crystallites. Such network would enhance the stability of the cathode composite and buffer spaces to accommodate the volume pulsation during charge/discharge cycling.