# Application of a New Polymer Particle Adhesive for Lithium Battery Separators
## 3 Results and Discussion
### Electrochemical Performance of Assembled Lithium Battery  
#### 3.5.1 Cyclic Voltammetry Analysis  
Figure 9 shows the cyclic voltammograms of lithium batteries assembled (LG3, LG4 and LS) with battery separators coated with G3, G4 and S-1. The lithium battery LS is a commercialized one, which is working as a control sample for the comparison with the ones we designed. The scanning speed was 0.1 mV/s and the scanning range was 2.2 V-4.4 V. Clearly, the lithium batteries prepared by the battery separators coated with  
Figure 8: Adhesion values between battery separators and pole pieces. As the coating process cannot be precisely controlled, the results in (**a**) show the adhesion between the pole pieces and battery separators coated with polymer particle adhesive (G3, G4 and S-1) of different coated areal density (see Table 3). In order to solve the problem, the author divides the adhesion values in (**a**) by corresponding coating surface density of the battery separators, and obtains the adhesion values between the pole piece and the battery separator under the unit coating surface density of polymer particle adhesions, which is (**b**).  
\begin{table}
\begin{tabular}{c c c c} \hline \hline
**Number** & **Tg (\({}^{\circ}\)C)** & **d\({}_{50}\) (\(\mu\)m)** & **Coated Areal Density (g/m\({}^{2}\))** \\ \hline G3 & 33 & 2.87 & 0.121 \\ \hline G4 & 58 & 4.16 & 0.183 \\ \hline S-1 & 61 & 5.1 & 0.22 \\ \hline \hline \end{tabular}
\end{table}
Table 3: The coated areal density of battery separator surface after wire rod coating.  
three kinds of polymer particle adhesive (G3, G4 and S-1) match the cyclic voltammetry curves of LiFePO\({}_{4}\). All of the lithium batteries show a pair of redox peaks in the scanning interval, corresponding to the charge/discharge process of iron phosphate/lithium iron phosphate [27; 28; 29]. It can be seen from Figure 9 that after the first cycle, the CV curves of the lithium battery have good coincidence and good cycle performance. In addition, it can be seen that the three kinds of lithium batteries have excellent reversibility through the peak shape of the redox peak. Therefore, it can be considered that the separators coated with different polymer binders have little effect on the cycle performance of the cathode material.  
Table 4 shows the data of peak voltage and potential difference in the cyclic voltammogram. The magnitude of the potential difference reflects the reversibility of the lithium battery. The potential difference of the lithium battery assembled by the battery separator coated with G3 is the smallest. This shows that the battery has the smallest polarization and the best reversible performance during the charging and discharging process.  
\begin{table}
\begin{tabular}{c c c c c c c c c c} \hline \hline  & \multicolumn{3}{c}{**1 st**} & \multicolumn{3}{c}{**2 nd**} & \multicolumn{3}{c}{**3 rd**} \\ \hline  & \multicolumn{2}{c}{**Peak Voltage**} & \multicolumn{2}{c}{**Potential**} & \multicolumn{2}{c}{**Peak Voltage**} & \multicolumn{2}{c}{**Potential**} & \multicolumn{2}{c}{**Peak Voltage**} & \multicolumn{2}{c}{**Potential**} \\  & \multicolumn{2}{c}{**Peak Voltage**} & \multicolumn{2}{c}{**Difference**} & \multicolumn{2}{c}{**Difference**} & \multicolumn{2}{c}{**Difference**} \\ \hline LG3 & 3.666 & 3.181 & 0.485 & 3.690 & 3.159 & 0.531 & 3.696 & 3.148 & 0.548 \\ \hline LG4 & 3.781 & 3.107 & 0.674 & 3.797 & 3.061 & 0.736 & 3.818 & 3.043 & 0.775 \\ \hline LS & 3.726 & 3.129 & 0.597 & 3.759 & 3.089 & 0.67 & 3.772 & 3.082 & 0.69 \\ \hline \hline \end{tabular}
\end{table}
Table 4: The data of peak voltage and potential difference in the cyclic voltammogram.  
Figure 9: The cyclic voltammograms of the assembled lithium batteries.