Research On ZnFe₂O₄/C As Anode Materials For Lithium-ion Batteries

Lithium-ion batteries?LIBs? are receiving considerable attention in applications, ranging from portable electronics to electric vehicles due to their superior energy density over other rechargeable battery technologies. The current choice of anode materials for LIBs is graphite due to its long cycle life, abundant material supply and relatively low cost. However, the graphite anode has the disadvantages of low theoretical capacity(372 mAhg^-1) and safety issues related to lithium deposition. Thus, there has been a growing interest in developing alternative anode materials. ZnFe₂O₄ have attracted extensive attention due to natural abundance, high theoretical capacity and low cost. However, the electrodes show a rather rapid capacity fading upon continuous galvanostatic cycling.Carbon coating is expected to be an effective strategy to improve electrochemical performance. It is reported that carbon coating can alleviate the volume expansion, suppress the aggregation of active particles and increase the electronic conductivity of the electrodes. In this paper, the main research contents and results are as follows:?1? ZnFe₂O₄/C has been synthesized by hydrothermal method and following calcination.X-ray diffraction and transmission electron microscopy indicate that the samples are well-crystallized spherical ZnFe₂O₄/C and the amorphous carbon layer is deposited on ZnFe₂O₄ particle surfaces through thermal decomposition of glucose. By comparing with adding different quality of glucose and different molar mass of C4H6O6 KNa and different sintering temperatures,ZnFe₂O₄/C that sintered at 600 ? with 0.4 g glucose and 0.5 mmol C4H6O6 KNa shows high reversible capacity of 578.5 m Ah g–1 at a current density of 100 m Ah g–1 after 100 cycles and good rate capability. This indicates the potential for the use of ZnFe₂O₄/C as anode materials for LIBs.?2? In this part, we have used fluorine-free, low cost, and non-toxic CMC as binder materialfor the electrode preparation, compared to the utilization of PVDF. The electrochemical performance was evaluated by cyclic voltammograms and galvanostatic discharge/charge testing.The electrode with CMC as binder material can deliver a discharge capacity of 742.5 mAhg^-1after 100 cycles at a current density of 100 mAg-1,which is superior to the PVDF.