Synthesis of micro-nano hierarchical structured LiFePO₄/C composite with both superior high-rate performance and high tap density

• Published in: Nanoscale 2011-01, Vol.3 (10), p.4434-4439
• Main Authors: Wang, Meng, Yang, Yong, Zhang, Youxiang
• Format: Article
• Language: English
• Subjects: Carbon - chemistry; Carbon-carbon composites; Discharge; Electric Power Supplies; Electrodes; Iron - chemistry; Lithium - chemistry; Lithium batteries; Nanocomposites; Nanomaterials; Nanostructure; Nanostructures - chemistry; Phosphates - chemistry; Precursors; Tap density
• ISSN: 2040-3364; 2040-3372
• DOI: 10.1039/c1nr10950b

Efforts were made to synthesize LiFePO(4)/C composites showing both high rate capability and high tap density. First, monoclinic phase FePO(4)·2H(2)O with micro-nano hierarchical structures are synthesized using a hydrothermal method, which are then lithiated to LiFePO(4)/C also with hierarchical structures by a simple rheological phase method. The primary structures of FePO(4)·2H(2)O are nanoplates with ∼30 nm thickness, and the secondary structures of the materials are intertwisted micro-scale rings. The LiFePO(4)/C materials lithiated from these specially structured precursors also have hierarchical structures, showing discharge capacities of more than 120, 110, and 90 mAh g(-1) at rates of 5 C, 10 C and 20 C, respectively, and high tap density of 1.4 g cm(-3) as cathode materials for lithium ion batteries. Since tap density is an important factor that needs to be considered in fabricating real batteries in industry, these hierarchical structured LiFePO(4)/C moves closer to real and large-scale applications.