Composite polymer electrolyte facilitated by enhanced amorphousity and Li+ conduction using LaFeO3-embedded PVDF-HFP for solid-state lithium metal battery.

Composite polymer electrolytes (CPEs) are a promising alternative to flammable conventional liquid electrolytes for high-safety lithium-ion batteries. Establishing low-cost filler that enhances the amorphous nature of polymer in the CPEs and exhibits efficient Lewis acid-base interaction between fillers and anions of lithium salt, leading to improved dissociation of salts for enhanced conduction, is indispensable. In this work, for the first time, we construct a solid composite polymer electrolyte of poly(vinylidene fluoride hexafluoropropylene) embedded LaFeO3 (LFO) particles prepared by solution casting and electrospinning methods and study their performances. The 5 wt% LFO filler embedded CPE made by means of solution casting and electrospinning methods exhibited the highest ionic conductivity of 5.9 × 10-4 and 1.49 × 10-3 S cm-1 at room temperature and electrochemical stability window up to 4.6 and 4.45 V, respectively. Further, as-assembled solid-state lithium-ion batteries using electrospun CPE showed an initial discharge capacity of 166 mAh/g at 0.1C-rate and solution-casted CPE showed excellent cycling stability with 98.6 % capacity retention at 0.3C-rate even at 50th cycle. Such excellent performance originated from the introduction of the LFO particles as filler into the polymer matrix to enhance the ionic conductivity, mechanical strength and lithium metal compatibility of the resulting CPEs.

Passive Filler-Loaded Silicon Oxycarbide Coating on Nickle Alloy with High Thermal Shocking Behavior and Oxidation Resistance.

Polymer-derived ceramic (PDC) coatings of considerable thickness can offer promising protection for metallic and superalloy substrates against oxidation and corrosion, yet the preparation remains challenging. Here, a SiOC/Al2O3/YSZ coating was prepared on a nickel alloy with a spraying method using Al2O3 and yttria-stabilized zirconia (YSZ) as passive fillers. The thickness can reach up to 97 µm with the optimal mass fraction and particle sizes of the passive fillers. A small or isolated SiOC phase is formed in the coating, which can effectively alleviate the shrinkage and cracking during the pyrolysis. The SiOC/Al2O3/YSZ coating exhibits low thermal conductivity and high bonding strength with the substrate. Moreover, the coating shows good thermal shock resistance between 800 °C-room temperature cycles and oxidation resistance at 1000 °C for 36 h. This work provides an effective guide for the design of thick PDC coatings to further promote their application in the thermal protective field.