Fabrication and electrochemical properties of 3D nano-network LiFePO_4@multiwalled carbon nanotube composite using risedronic acid as the phosphorus source

LiFePO₄@multiwalled carbon nanotubes (email protected]) 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 (D_Li⁺) 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 email protected] resulted from using RDA as a new phosphorus source.