Synthesis and Characterization of Pitch-Coated Li2MnxFe1−xSiO4/C Composite Cathode Material for Lithium-Ion Batteries

Abstract

In this study, two cathode materials were synthesized (Li 2 Mn 0.5 Fe 0.5 SiO 4 and Li 2 Mn 0.2 Fe 0.8 SiO 4 ). The intrinsic characteristics and electrochemical performance of these materials were investigated. These silicate cathode materials have several advantages such as high safety, low cost, low environmental toxicity, and high theoretical energy density. However, they have some drawbacks that must be addressed, including low electronic conductivity and low ionic diffusivity, which limit their practical application in lithium-ion batteries. The Li 2 Mn x Fe 1−x SiO 4 /C composite materials were prepared using the sol-gel method. The X-ray diffraction patterns of the synthesized Li 2 Mn x Fe 1-x SiO 4 /C composite materials exhibited favorable crystallinity. Pitch was coated on the synthesized composite materials to improve their electronic conductivity. Raman spectroscopy confirmed the high graphitization of the carbon coatings. The discharge capacity of the pitch-coated Li 2 Mn 0.2 Fe 0.8 SiO 4 /C (Li 2 Mn 0.2 Fe 0.8 SiO 4 /C/pitch) cathode was 183 mAh g −1 delivered in the first cycle at a rate of 0.1 C. The battery cycle retention was 85% after 30 cycles, demonstrating an excellent cycle life compared with those reported in previous studies. These cathode materials have high potential for application in lithium-ion batteries.

Soft carbon in non-aqueous rechargeable batteries: a review of its synthesis, carbonization mechanism, characterization, and multifarious applications

“…The benefits of soft carbon coating have also been harnessed for other polyanionic cathodes, like Li 2 FeSiO 4 , Li 2 Mn x Fe 1− x SiO 4 , and Li 2 FeP 2 O 7 . 152–154 The improvements in the electrochemical performances of all the polyanionic cathode materials discussed here are summarized in Table 5.…”