FeF3•0.33H2O@carbon nanosheets with honeycomb architectures for high-capacity lithium-ion cathode storage by enhanced pseudocapacitance

There is an increasing demand for current and future applications to obtain charge storage devices with both energy and power superiority. Recently, several high-rate pseudocapacitive anode materials for Li-ion batteries have been reported; however, the research on the pseudocapacitive properties of cathode materials is much less common. Herein, an FeF3 center dot 0.33H(2)O@CNS (carbon nanosheet) composite, where ultrafine FeF3 center dot 0.33H(2)O particles are intimately embedded into nitrogen-doped carbon nanosheets, was successfully designed and fabricated. The pseudocapacitive effect of the composite cathode was demonstrated and explored by its Li+ storage kinetic analysis. The results demonstrated that the FeF3 center dot 0.33H(2)O@CNS cathode with a higher capacitance distribution rate than bare FeF3 center dot 0.33H(2)O provides higher rate performance with discharge capacities of 235, 175, and 143 mA h g(-1) at 0.1C, 1C, and 5C, respectively. It also displayed an excellent cycle performance (capacity retention of 97.2% at 1C after 200 cycles). FeF3 center dot 0.33H(2)O@CNS//LCNS full cells combined with pre-lithiated carbon nanosheets (LCNSs) also exhibit excellent electrochemical performance. Therefore, the electrochemical performance of cathode materials can be improved by adjusting their pseudocapacitive contribution, which represents a promising and effective strategy for obtaining electrode materials with high energy and high-power densities.