Fabrication and electrochemical properties of 3D nano-network LiFePO4@multiwalled carbon nanotube composite using risedronic acid as the phosphorus source

• Published in: Progress in natural science 2019-04, Vol.29 (2), p.156-162
• Main Authors: He, Liping, Zha, Wenke, Chen, Dachuan
• Format: Article
• Language: English
• Subjects: 3D nano-network; Electrochemical properties; LiFePO4@multiwalled nanotube; Lithium-ion battery; Risedronic acid
• ISSN: 1002-0071
• DOI: 10.1016/j.pnsc.2019.02.005

LiFePO4@multiwalled carbon nanotubes (LFP@MWCNTs) nanocomposite has been fabricated using risedronic acid (RDA) as a new eco-friendly phosphorus source. Microscopic, spectroscopic, and electrochemical characterization demonstrate that the MWCNTs are in the form of coiled and cross-linking nanoribbon, which wrapped and encrusted around LiFePO4 particles to form a three-dimensional (3D) nano-network composite. This microstructure of 3D nano-network is obtained due to the reactions between RDA's special functional groups with Fe2+ and COH, CO or COOH on the surface of the functionalized MWCNTs. The results also show that the particle size of the fabricated LiFePO4@MWCNTs composite is below 300 nm with the pure crystal of olivine. This nanocomposite indicates an enhanced reversible capacity of 162.2 mAh g−1 at 0.2 C, and high capacity retention of 76.5% even at 10 C after the 800th cycles. The electric conductivity and Li+ diffusion coefficient (DLi+) of the LiFePO4@MWCNTs are 3.79 × 10−2 S cm−1 and 4.46 × 10−11 cm2 s−1, respectively. These improved electrochemical parameters can be attributed to the nano-sized effect of particles, MWCNTs' wrapping effect and 3D nano-network microstructure of the LFP@MWCNTs resulted from using RDA as a new phosphorus source. [Display omitted] •Developed a method of fabricating LFP@MWCNTs using RDA as new phosphorus source.•LFP@MWCNTs exhibits uniform nanosphere with a unique 3D nano-network structure.•Formation 3D nano-network structure is resulted from RDA's special functional groups.•Good electrochemical properties of LFP@MWCNTs is owing to the unique 3D nano-network.•LFP@MWCNTs exhibits enhanced electrical conductivity and Li+ diffusion coefficient.