g-C₃N₄ nanosheets enhanced solid polymer electrolytes with excellent electrochemical performance, mechanical properties, and thermal stability

Abstract

g-C3N4 nanosheets are used as solid electrolyte filler for the first time.

Flexible, high-voltage, ion-conducting composite membranes with 3D aramid nanofiber frameworks for stable all-solid-state lithium metal batteries

“…The deformation of the charge/discharge curves caused the great increase of the charge potential and the decrease of the discharge potential, and thus can be also regarded as a polarization behavior. Moreover, the deformation became more and more severe with increasing charge/ discharge cycle number or current density, consistent with the previous studies [15,56,91,92]. Actually the ANF/ PEO-FF and ANF/PEO-DF electrolyte-based cells also showed the similar yet non-severe deformation at high current densities of 0.5-1.0 C ( Fig.…”

“…Based on these analyses and other reports on the high stability of the LiFePO 4 cathodes [56,72], one can easily conclude that the deformation is not related to the LiFePO 4 cathode but the electrolyte. Previous studies usually ascribed to the high polarization (or severe charge/discharge curve deformation) to the increase of the internal resistance of the battery and the low Li + ion diffusivity in the solidstate electrolyte and the electrolyte/electrode interface [15,56,72,[91][92][93]. Note that all the solid-state cells exhibited much higher Coulombic efficiencies of nearly 100% during the whole cycling than the traditional LIBs with the organic liquid electrolytes (Fig.…”

“…Further, the ANF/ PEO-DF CPE membrane with higher ANF content exhibited the highest ultimate tensile strength of 10.0 MPa. The mechanical strength of the ANF framework-based CPE membranes was comparable to those of the commercial PP/PE separators and much higher than those of other nanoparticle-filled CPEs such as aluminosilicate nanoparticle [52], Mg 2 B 2 O 5 nanowire [55], g-C 3 N 4 nanosheet [56], and 3D PEO-grafted polyimide scaffold [5]. The ANF/PEO-DF and ANF/PEO-FF CPE membranes also exhibited greatly enhanced Young's modulus of 33.4 and 17.0 MPa, which were 83.5 and 42.5 times higher than that of the pristine PEO-LiTFSI electrolyte membrane (0.4 MPa), respectively.…”

High-Performance Solid Composite Polymer Electrolyte for all Solid-State Lithium Battery Through Facile Microstructure Regulation

“…The solid composite polymer electrolyte with 10% g-C 3 N 4 exhibited the maximum ionic conductivity (1.76 × 10 −5 S cm −1 ) at 25°C, and the conductivity reached to about 1.08 × 10 −3 S cm −1 at 100°C. And this ionic conductivity at room temperature was much higher than that of the recently reported PEO/g-C 3 N 4 /LiTFSI solid electrolytes (2.3 × 10 −6 S cm −1 , at 30°C) (Sun et al, 2019). Also this ionic conductivity is nearly close to that (2.2 × 10 −5 S cm −1 at 28°C) of the PEO based solid composite electrolyte, which needed LiTFSI as the lithium salt and 2D MXene as the filler (Pan et al, 2019).…”

“…On the other hand, Figure 9B demonstrated that the cell based on the solid composite polymer electrolyte with a capacity retention ratio of 80% after 200 cycles possessed an initial discharge capacity of 161.2 mAh g −1 , which was very close to the theoretical capacity of LiFePO 4 (170 mAh g −1 ). Moreover, this cycling performance was better than the reported LiFePO 4 /Li solid-state batteries based on PEO-LiTFSI-g-C 3 N 4 polymer electrolytes, which gave an initial discharge specific capacity of 161.3 mAh g −1 but cycled for 120 cycles at 60°C (Sun et al, 2019). The coulombic efficiency of batteries based on the solid composite polymer electrolyte during charge-discharge cycling test was as high as 99.7% in Figure 9B, which was higher than that of the battery based on the PEO-LiClO 4 electrolyte shown in Figure 9A.…”