Ruyan Lei,Yanping Yang,Chenjuan Yu,Yinsi Xu,Yuanzhuo Li,Jun Li
In order to improve the electrochemical performance and efficiently prepare a solid polymer electrolyte (SPE) for the lithium-metal battery (LMB), a fumed SiO2 (FS) with surface Si–OH group was used to fabricate FS-modified poly(ethylene oxide) (PEO)–LiClO4-based SPE by a facile preparation process. The influences of the FS content on the morphological properties, thermal properties, lithium salt dissociation, mechanical properties, and electrochemical properties of SPE were systematically analyzed. Results indicate that FS with the hydrophilic property was widely distributed throughout the amorphous phase of SPE, thus the crystallinity of SPE was reduced to 25.83% when the FS mass loading was 6.85 wt%. In addition, a greater dissociation degree of lithium salt was achieved after the addition of FS, and a higher ion conductivity of 3.03 × 10−4 S cm−1 and Li-ion migration number of 0.396 were recorded at 60 °C. The all-solid-state Li/SPE/Li coin cell showed excellent stable cyclability (380 h) and the LiFePO4 (LFP)/SPE/Li coin cell demonstrated good discharge specific capacity and coulomb efficiency of 96 mA h g−1 and 100.2%, respectively, after 100 cycles of galvanostatic charge–discharge operation under 0.5C at 60 °C. Thus, based on collective results, it is expected that SPE presented in this work is a promising electrolyte for next-generation high-energy all-solid-state LMB with enhanced safety.
Jun-Wei Zha,Na Huang,Kang-Qiang He,Zhi-Min Dang,Chang-Yong Shi,Robert KwokYiu Li
Solid polymer electrolytes (SPEs) have great potential to address the safety issues of lithium (Li)-ion batteries when compared with conventional liquid electrolytes, which makes them a promising alternative for next-generation high-energy batteries. In this work, poly(ethylene oxide)-lithium perchlorate (PEO–LiClO 4 ) polymer electrolytes for Li-ion batteries were prepared using electrospinning. The crystallinity, ionic conductivity as well as mechanical properties were investigated. Ionic conductivities and mechanical properties of PEO–LiClO 4 based SPE have been obviously increased by incorporating modified TiO 2 nanofibres (TNFs) than TiO 2 nanoparticles (TNPs), due to that both TNFs and TNPs can decrease the crystalline phase concentration of PEO and increase segmental flexibility of PEO. The SPE with 3 wt% TNFs exhibits the highest conductivity of 5.308 × 10 −5 S cm −1 at 20°C and higher tensile strength of 13.8 MPa. These results highlight the potential of utilising the electrospinning method to improve the ionic conductivity of SPEs.
Much attention has been directed toward the development of electrically controlled solid propellant (ECSP) as it can implement switched on–off as well as regulation of burning rate. In this work, sodium/lithium battery-inspired sodium perchlorate (SP)/lithium perchlorate (LP)-based ECSPs were prepared and characterized. Herein, an ignition-combustion-extinguishment cycle is referred to a stage. The properties of electroconductibility and multi-stage combustion for ECSPs were investigated, utilizing electrochemical impedance spectroscopy (EIS) and electrically controlled combustion test system. Results demonstrated that the component compatibility and conductivity of ECSP were optimal as m SP : m LP = 1:1, excellently eliminating the crystallization problem of the propellant. The ignition/extinguishment delay time of the second stage was always significantly lower than that of the first stage, whereas the adjustable capability of the burning rate of the second stage was slightly better than that of the first stage (100 V ∼ 200 V). Meanwhile, it was found that there was a positive correlation of the burning rate vs the electrical conductivity in the combustion stable stage. In Addition, the concentration gradient of anions/cations and the composition of surface compounds of different layers were analyzed by energy dispersive spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS) and discharge test of ECSP-supercapacitor. Accordingly, the multi-stage electrothermal combustion mechanism model was established, revealing that ion transfer, electron exchange, ohmic heating and PVA gel flame-retardation are the four major factors affecting the controllable combustion of ECSP.
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