A Heterostructured Gel Polymer Electrolyte Modified by MoS2 for High-Performance Lithium-Sulfur Batteries.

In Li-S batteries, the shuttle effect of polysulfide lithium (LiPS) on the cathode side and the growth of lithium dendrites on the anode side are two major problems that lead to an insufficient cycle life. Herein, in light of the challenges brought on by the different chemical environments on both sides of Li-S batteries, a heterostructured poly(ethyl acrylate-co-ionic liquid) gel electrolyte with a single-sided electrocatalytic reduced graphene oxide/MoS2 coating (MoS2@rGO-GPE) was developed in order to assemble a high-performance Li-S battery with a self-supporting graphene sulfur cathode. In such a device architecture, there is multiposition suppression of the shuttle effect; that is, the confinement of the graphene foam, the catalysis of the MoS2 composite, and the capture of the gel polymer electrolyte. Our results show that the ionic conductivity of the heterostructured electrolyte is 1.98 mS cm-1, and the Li ion transference number reaches 0.81. The assembled lithium-sulfur battery displays a high initial discharge capacity of 1027 mAh g-1 at 0.1 C, superior cycle stability (80% capacity retention after 500 cycles), and excellent rate performance. This design strategy provides a valuable route for the development of high-performance lithium-sulfur batteries.

Rearrangement of Ion Transport Path on Nano-Cross-linker for All-Solid-State Electrolyte with High Room Temperature Ionic Conductivity.

The low room temperature ionic conductivity (RTσ) of polyethylene oxide (PEO)-based solid-state polymer electrolyte (SPE) severely restricts its application for lithium batteries. Herein, acrylamide (AM) has been introduced into the poly(ethylene glycol) methyl ether methacrylate-poly(ethylene glycol) diacrylate (P-P). The multiple hydrogen bonds of AM expand the original single lithium environment (Li···O-C) to three types (Li···O-C, Li···N-H, and Li···O═C), which accelerates the conduction of lithium ions. In addition, the double bond modification of nanosilica (═SiO2) not only improves the mechanical properties but also brings a high-speed orderly vehicular transport mechanism. The multiple-lithium-ions environment is rearranged on the surface of the ═SiO2 to play a more significant role, making the RTσ of SPE reach 2.6 × 10-4 S cm-1, and the Li-ion transfer number reaches 0.84. The results show that the assembled all-solid-state lithium-sulfur battery has a high initial discharge capacity of 707 mAh g-1 at 30 °C when the sulfur loading is 4.3 mg cm-2, good cycle stability (capacity retention rate of 89% after 100 cycles at 0.1 C), and excellent rate performance. This SPE with high RTσ, stable interface engineering, and broad potential window (5.1 V) is expected to be used in other lithium/lithium-ion batteries that require high-voltage tolerance.