# Application of a New Polymer Particle Adhesive for Lithium Battery Separators
## 3 Results and Discussion
### Electrochemical Performance of Assembled Lithium Battery
#### 3.5.3 Charge and Discharge Performance Test  
Figure 11 shows the cyclic performance curves of assembled lithium batteries at different discharge rates. The data relating to discharge capacity and capacity retention rates of assembled lithium batteries at different discharge rates are shown in Table 6. As can be seen from Figure 11 and Table 6, the discharge capacity of the assembled lithium batteries gradually decreases when the discharge rates increases. The discharge capacities of the assembled lithium batteries (LG3, LG4 and LS) are higher than those of the assembled lithium batteries prepared by the separators coated without polymer particles adhesives (Uncoated) when the discharge rate is 0.2 C or 0.5 C. Furthermore, there is little difference in discharge capacity of the assembled lithium batteries when the discharge rate is 1 C. The reason for this phenomenon could be that the polymer particle adhesives on the separator are conducive to close contact with the material (LiFePO4) on the positive electrode sheet, which can shorten the transmission path of lithium ions. In addition, the polar functional groups on the polymer particle adhesives can increase the wettability of the separator, making the separator and electrolyte wetting better, so that the lithium ions move rapidly during the charging and discharging process. However, when the discharge rate is 2 C, the discharge capacity of the lithium battery LS is 107.2 mAhg\({}^{-1}\), which is significantly lower than that of the other three lithium batteries. This is because there are too many polymer particle adhesives (S-1) coated on the separator in the lithium battery LS, which blocks the micropores on the separator and affects the shuttle of lithium ions. Figure 12 shows the capacity retention rate of assembled lithium batteries at different discharge rates. As can be seen from Figure 12 and Table 6, the capacity retention rate of the assembled lithium battery LG3 at different discharge rates is more than 99%, which is greater than that of the other three lithium batteries. In addition, the capacity retention rates of the assembled lithium batteries LG4, LS and Uncoated are basically the same. This shows that the coating of polymer particle adhesives (G3, G4 or S-1) on the battery separator does not affect the capacity retention rate of the assembled lithium batteries. \begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline  & \multicolumn{3}{c}{**Discharge Capacity/mAhg\({}^{-1}\)**} & \multicolumn{3}{c}{**Capacity Retention Rate/\%**} \\ \hline  & 0.2 C & 0.5 C & 1 C & 2 C & 0.2 C & 0.5 C & 1 C & 2 C \\ \hline Uncoated & 145.3 & 143.6 & 139 & 120.5 & 99.2 & 100.53 & 91.07 & 98.96 \\ \hline LG3 & 145.3 & 150.5 & 142.2 & 124.3 & 99.2 & 99.44 & 100.2 & 99.2 \\ \hline LG4 & 145.3 & 146.2 & 137.7 & 123.8 & 99.2 & 99.49 & 99.36 & 98.6 \\ \hline LS & 145.3 & 149 & 137.6 & 107.2 & 99.2 & 98.7 & 98.5 & 96 \\ \hline \hline \end{tabular}  
* After 100 cycles of charge and discharge.  
\end{table} 
Table 6: The data of discharge capacity and capacity retention rate of assembled lithium batteries at different discharge rates. Figure 12: The capacity retention rate of assembled lithium batteries at different discharge rates. (**a**) shows the capacity retention rate of lithium battery at different discharge rates when the lithium battery separator was not coated without any polymer particle adhesives; (**b**) shows the capacity retention rate of lithium battery LG3 at different discharge rates when the lithium battery separator was coated with polymer particle adhesive G3; (**c**) shows the capacity retention rate of lithium battery LG4 at different discharge rates when the lithium battery separator was coated with polymer particle adhesive G4; (**d**) shows the capacity retention rate of lithium battery LS at different discharge rates when the lithium battery separator was coated with polymer particle adhesive S-1.