The top-and cross-section SEM images of the Li electrodes from both cells after cycling (Li|SPE10:1:1|Li cell for 60 cycles, Li|SPE10:1:1-CL|Li cell for 130 cycles) are shown in Figure -f. In the Li|SPE10:1:1|Li cell, the electrode surface displays large cracks and mossy Li formations (Fig. ), whereas the Li|SPE10:1:1-CL|Li cell shows a smooth and dense Li metal surface (Fig. ), indicating a uniform Li plating-stripping process. The cross-section images revealed a thick layer of dendritic/dead Li at the interface of the Li|SPE10:1:1|Li cell (Fig. ), in contrast to a dense and uniform interface observed in the Li|SPE10:1:1-CL|Li cell (Fig. ). This confirmed the formation of a smooth and compact interphase and SEI layer in the cell with crosslinked SPE10:1:1-CL, contributing to its good cycling performance. UVcrosslinking appears to play a crucial role in suppressing Li-dendrite formation and facilitating facile and reversible Li plating-stripping. The prepared SPE10:1:1 and SPE10:1:1-CL membranes were first incorporated into high loading (6 mg cm -2 ) LFP||Li cells to investigate their performance in solid-state LMBs. Figure presents the prolonged cycling results for both LFP|SPE10:1:1|Li and LFP|SPE10:1:1-CL|Li cells at 0.1 C (0.05 mA cm -2 current density). The LFP|SPE10:1:1-CL|Li cell incorporating a crosslinked membrane exhibits an initial discharge capacity of 160 mAh g -1 , maintaining 90% of its capacity after 100 cycles, achieving excellent coulombic efficiency of nearly 99.8% throughout cycling. In contrast, the LFP|SPE10:1:1|Li cell with non-crosslinked membrane exhibits an initial capacity of 158 mAh g -1 but experienced a short circuit after 42 cycles. Figure shows the charge-discharge profiles of the LFP|SPE10:1:1-CL|Li cell at different cycle numbers, noting that while the discharge capacity decreased, the charge and discharge curves remained very stable over 100 cycles. A rate capability test, detailed in Figure , was conducted at current densities of 0.05 to 1 mA cm -2 (1C equals 1 mA cm -2 ). Compared to the LFP|SPE10:1:1|Li cells, the LFP|SPE10:1:1-CL|Li cells exhibited improved rate capability, maintaining nearly full capacity at 0.05C. Overall, the battery delivered high discharge capacity ranging from 170-59 mAh g -1 at 0.05 to 1C. Figure presents charge-discharge profiles of the LFP|SPE10:1:1-CL|Li cell at various C-rates within a voltage range of 2.5-4.0 V vs. Li + /Li, showing stable potential plateaus and increasing overpotential with higher C rates. AC impedance profiles (Figure ) showed a steady decrease in interfacial resistance from 0.05C to 0.2C as the crosslinked membrane adapted itself with the electrode, followed by a slight increase at 0.5C and 1C rate due to interface stability. The improved rate performance and cycling stability of the LFP|SPE10:1:1-CL|Li cell demonstrate the advantages of the crosslinked SPE10:1:1-CL, providing superior electrochemical stability at 50°C.