Engineering 3D Interpenetrated ZIF‑8 Network in Poly(ethylene oxide) Composite Electrolyte for Fast Lithium-Ion Conduction and Effective Lithium-Dendrite Inhibition

A novel 3D ZIF-8 network-reinforced polyethylene oxide (PEO) composite polymer electrolyte (Z-C-PAN-PEO) is successfully built, in which the network with an interpenetrated structure is tactfully developed by in situ assembling ZIF-8 nanoparticles on electrospinning carboxylated polyacrylonitrile (C-PAN) nanofiber surfaces. ZIF-8 with high porosity and unsaturated open metal sites will act as the bridge between C-PAN nanofibers and the PEO matrix. It is proven that the selected ZIF-8 can play a significant role in facilitating Li+ conduction and transference by effectively interacting with the oxygen atoms of C–O–C to promote the segmental movement of PEO and immobilizing TFSI– anions to release more free Li+. The 3D interpenetrating structure of Z-C-PAN further enables the conduction channels more consecutive and long-ranged, endowing the Z-C-PAN-PEO electrolyte with an optimum ionic conductivity of 4.39 × 10–4 S cm–1 and a boosted Li+ transference number of 0.42 at 60 °C. Other improvements occurring in the reinforced electrolytes are the broaden electrochemical stability window of ∼4.9 V and sufficient mechanical strength. Consequently, the stable Li-plating/stripping for 1000 cycles at 0.1 mA cm–1 witnesses the splendid compatibility against Li dendrite. The cycling performance of LiFePO4/Z-C-PAN-PEO/Li cells with a reversible capacity of 116.2 mAh g–1 after 600 cycles at 0.2 C guarantees the long-term running potential in lithium metal batteries. This study puts forward new insights in designing and exploiting the active role of MOFs for high-performance solid polymer electrolytes

CeF₃‑Doped Porous Carbon Nanofibers as Sulfur Immobilizers in Cathode Material for High-Performance Lithium–Sulfur Batteries

In this study, the CeF₃-doped porous carbon nanofibers (PCNFs), prepared via electroblown spinning technique and carbonization process, are used as sulfur immobilizers in cathodes for lithium–sulfur (Li–S) batteries for the first time. The cathode composed of CeF₃-doped PCNFs, carbon nanotubes (CNTs), and S is successfully prepared through the ball-milling and heating method. The formed porous structure in the PCNFs and CNTs facilitates the construction of highly electrically conductive pathways and effectively alleviates volume changes, which can maintain the stability of the cathode structure and make them in close contact between the electrodes. Meanwhile, the intermediate polysulfide dissolved and lost in the electrolyte can also be suppressed because of the hierarchical porous carbon nanofibers and CeF₃. The Li–S battery using the cathode can display excellent electrochemical properties and stable capacity retention, presenting an initial discharge capacity of 1395.0 mAh g^–1 and retaining a capacity of 901.2 mAh g^–1 after 500 cycles at 0.5C. During the rate capability tests of battery, the discharge capacity of Li–S battery with the electrode slowed down from the discharge capacity of 1284.6 mAh g^–1 at 0.5C to 1038.6 mAh g^–1 at 1C and 819.3 mAh g^–1 at 2C, respectively. It is noteworthy that the battery can still endow an outstanding discharge capacity of 1269.73 mAh g^–1 with a high retention of 99.2% when the current density returns to 0.5C