## 3 Results
BMEP is coupled with PUA-PUMA between phosphate groups. The ability of the GPEs to completely bend after swelling in the LiPF\({}_{6}\) electrolyte is another way that Figure 1 demonstrates the flexibility of the GPEs. Since all evaluated samples show exceptional mechanical stability, the membranes can maintain their integrity even at thin thicknesses of about 25 \(\upmu\)m when dry and about 30 \(\upmu\)m when in gel form. According to the mechanical testing (Elastic Modulus Method), the crosslinking densities for PP1, PP2, and PP3 membranes were found to be 360,252, 446,853, and 404,897 mol/m\({}^{3}\), respectively. The primary objective in the selection of electrolyte materials is ionic conductivity, a crucial parameter required for the efficient electrochemical operation of batteries. Electrochemical impedance spectroscopy experiments were conducted at ambient temperature using stainless-steel electrodes employed as blocking electrodes (SS/GPE/SS) to assess the conductive properties of gel polymer electrolytes. All of the GPE samples' impedance spectra showed similar plots, and the bulk resistance (Rb) and the interfacial transition resistance had a significant impact on the battery's electrochemical performance. The pronounced significance of Rb in the overall impedance values is visually depicted in Figure 6a. Using the impedance spectroscopy results, ionic conductivity values for GPEs were calculated and are listed in Table 2.  
Each GPE sample exhibited an initial thickness of approximately 30 \(\upmu\)m prior to their assembly into coin cells. The incorporation of bis[2-(methacryloloxy)ethyl] phosphate into the GPE structure resulted in noticeable enhancements in conductivity values. This increase is explained by porosity and the increased absorption of liquid electrolytes, both of which contribute to the polymer electrolyte's overall improvement in ionic conductivity. Notably, among the various GPE samples, the GPP2 membrane displayed the highest recorded conductivity, measuring at 1.83 \(\times\) 10\({}^{-3}\) S cm\({}^{-1}\). This conductivity level significantly exceeds that of Celgard2500, a commercial separator membrane, which registered a conductivity of 0.36 \(\times\) 10\({}^{-3}\) S cm\({}^{-1}\)[35]. When a higher percentage of BMEP is added to the structural framework, the crosslinking density increases significantly, which accounts for the GPP3 membrane's reduced ionic conductivity. As a result, the absorption of electrolytes was inhibited. Linear sweep voltammetry curves in the Li/GPE/SS blocking cell configuration at a potential range of 2 to 6 V at 25 \({}^{\circ}\)C are representative of the electrochemical stability window of the GPP2 electrolyte. In the scan potential range of 2 V to 3.78 V, as shown in Figure 6b, there is no observable response from the current. It is stable enough to use as the electrolyte material in lithium batteries, with an electrochemical window of 3.78 V for the GPP2 electrolyte. Our goal for the future is to fully investigate the electrochemical performance of the new polymer electrolyte, which is essential to the assembly of the entire battery cell. Figure 6c displays the cell's initial charge-discharge characteristics with GPP2 at a 0.1 C rate (25 \({}^{\circ}\)C, 2.7-4.2 V). Flat charge and discharge potential plateaus were seen in the unit cells at 3.43 and 3.33 V, respectively. At 0.1 C, the cell had initial discharge capabilities of 149 mAh g\({}^{-1}\). Approximately 88% of LiFePO\({}_{4}\)'s theoretical capacity (170 mA h g\({}^{-1}\)) is represented by these values. Step-by-step variations in charging currents from 0.1 C to 1 C every five cycles were used to examine the rate capacity of the GPP2-containing cell (Figure 6d). With specific discharge capacities of 149, 138, 125, and 109 mA h g\({}^{-1}\) at 0.1, 0.2, 0.5, and 1 C, respectively, the Li/GPP2/LiFePO\({}_{4}\) cell is shown to have outstanding rate performance.