Preparation And Electrochemical Performance Research Of Anode Slurries For Lithium Ion Slurry Cells

It is necessary to reduce the dependence on fossil energy and develop renewable energy because over-exploitation of fossil energy has seriously worsened the environment and climate.However,renewable energy sources such as solar energy and wind energy are instable and discontinuous which cannot be directly integrated into the power grid.As a result,a large amount of photovoltaic and wind power has been wasted.Therefore,it is urgent to develop large-scale energy storage methods to store renewable energy and output the power into power grid steadily and continuously during peak periods of electricity consumption.Lithium-ion slurry cell(LSFC)is a new type of flow battery,which has the advantages of high energy density,energy and power can be designed independently,to name but a few.However,due to its system complexity,lithium ion slurry battery has a series of problems such as poor stability,poor rate capability,and so on.Based on this,anode slurries for lithium ion slurries battery were studied in this paper including preparing of graphite slurry and lithium titanate slurry.And then the electrochemical performance of the two prepared anode slurries were studied.Using graphite as active material,preparation method of graphite slurry and its electrochemical performance were studied.The performance of the slurry prepared by ball milling and magnetic stirring was compared,and the effect of the KB content of the conductive agent in the slurry on its performance was studied.The result indicated that using the ball milling method and when the KB content was 1.4%-1.6%,continuous three-dimensional conductive network can be formed in the slurry and it performs well in terms of stability,fluidity,and conductivity.Electrochemical performance of batteries assembled with this slurry are tested.The cyclic voltammetry(CV)results showed that the curves are similar with that of half-cells with graphite as active material in traditional lithium-ion batteries,indicating that the graphite in the slurry can normally exhibit electrochemical activity.The charge-discharge performance test showed that the initial coulomb efficiency was 48.3%,the initial charge capacity was 294 m Ah/g,and the specific capacity after 285 cycles at 0.2 C remained at 138.4 m Ah/g.The rate performance test showed that the performance below 1 C is satisfying,and it can exert more than half of its theoretical capacity.While at higher C rates such as 2 C,the capacity decline obviouslyUsing lithium titanate(LTO)as the active material,preparation method of lithium titanate slurry and its electrochemical performance were studied.The performance of the slurry prepared by ball milling and magnetic stirring was compared Conductivity and AC impedance are tested on LTO slurry,and charge and discharge performance test were performed on the slurry cell.The results indicate that the LTO slurry prepared by ball milling has stronger stability,higher conductivity,lower impedance and better electrochemical performance.By adding 1% polyethylene oxide(PEO),conductivity of the slurry was further improved,the impedance is reduced,and the cycle stability is enhanced.The ball milling method and the addition of 1% PEO were used to prepare a LTO slurry assembled battery test.The electrochemical test results show that the slurry battery can attain a specific capacity of 156.7 m Ah/g at 0.2 C.The capacity retention rate of 200 cycles is 72.4%.In conclusion,we explored the slurries anode preparation method for slurry flow cells,and studied their electrochemical performance,which is hoped to set some foundation for the future research on the similar systems.