Three-Dimensional Carbon-Coated LiFePO4 Cathode with Improved Li-Ion Battery Performance

First-principles study of LiFePO4 modified by graphene and defective graphene oxide

The energy stability and electronic structural of graphene and defective graphene oxide (GO) parallel to the surface of LiFePO4 (010) were theoretically investigated by using first-principles density functional theory calculations within the DFT + U framework. The calculated formation energy shows that GO coating on the surface of LiFePO4 (010) is energetically favorable and has higher bond strength compared to graphene. The calculation of the electronic structure indicates that the emergence of band in-gap states originates from graphene coating, with adsorbed O atoms contributing significantly above the Fermi level. Electron density difference indicate that GO stands on the LFP (010) surface through C-O and Fe-O bonds, rather than relying on van der Waals forces placed parallel to the LFP crystal, with the chemical bond at the LFP/GO interface (Fe-O-C) both anchoring the coated carbon layer and promoting electron conductivity at the interface. In addition, LFP/GO shows superior electrochemical performance, Atomic Populations suggests that the average Fe-O bonding on the surface of LiFePO4 (010) was clearly changed after graphene or GO coating, which led to the expansion of Li+ channels and favored the migration insertion and extraction of Li+.

A Review on Electrode Materials of Fast-Charging Lithium-Ion batteries

In recent years, the driving range of electric vehicles (EVs) has been dramatically improved. But the large-scale adoption of EVs still is hindered by long charging time. The high-energy LIBs are unable to be safely fast-charged due to their electrode materials with unsatisfactory rate performance. Thus it is necessary to summarize the properties of cathode and anode materials of fast-charging LIBs. In this review, we summarize the background, the fundamentals, electrode materials and future development of fast-charging LIBs. First, we introduce the research background and the physicochemical basics for fast-charging LIBs. Second, typical cathode materials of LIBs and the method to enhancing their fast-charging properties are discussed. Third, the anode materials of LIBs and the strategies for improving their fast-charging performance are analyzed. Finally, the future development of the cathode materials in fast-charging LIBs is prospected.