Kuo Yang,Hao Su,Mingtao Ding,Ye Li,Bing Xue,Xiaopeng Gu
Nickel–iron based layered double hydroxide (NILDH) was used for the first time as an inorganic filler to prepare poly(ethylene-oxide)/nickel–iron based layered double hydroxide (PEO/NILDH) composites to improve the properties of PEO-based solid electrolytes. The SEM micrographs and EDS images confirmed the homogeneous dispersion of NILDH particles in the PEO matrix. The XRD and DSC results indicated that the PEO crystallinity tended to decrease with the increase in the amount of NILDH. Meanwhile, the addition of NILDH promoted the improvement of ionic conductivity for PEO/NILDH composites and the maximum value (1.644 × 10−4 S cm−1) appeared at the NILDH concentration of 10 wt%. NILDH with a positive charge surface could increase the lithium-ion transference number by attracting and anchoring the anion of LiTFSI. Meanwhile, the formation of amorphous regions around NILDH was beneficial for the Li+ ion conduction. Furthermore, the electrochemical stability windows of the composite electrolyte were increased to 5.2 V after the addition of NILDH, and the all-solid-state lithium battery using this composite electrolyte showed a specific capacity of 148 mA h g−1 and better cycling performance. The tensile strength of PEO/NILDH composites was enhanced when NILDH was introduced into the PEO matrix with a filler loading of not more than 10 wt%. The remarkable properties of the PEO/NILDH composite make it a potential solid electrolyte material for lithium-ion batteries.
Zheng Zhang,Shundong Guan,Sijie Liu,Bingkun Hu,Chuanjiao Xue,Xinbin Wu,Kaihua Wen,Ce-Wen Nan,Liangliang Li
Li metal is the next-generation anode material for high-energy-density Li-ion batteries. Unfortunately, its practical application is hampered by drawbacks such as an unstable solid electrolyte interphase and undesirable Li dendrites. Herein, an Fe-based protective layer with a valence gradient is constructed on Li anodes, which consists of an Fe 3+ /Fe 2+ -rich outer layer and an Fe 0 -containing inner layer. The protective layer not only isolates the underlying Li metal from the corrosive carbonate electrolyte, but also uniformly stores Li during plating and inhibits the growth of Li dendrites. The Li anode with the Fe-based protective layer shows dendrite-free Li plating/stripping behaviors; therefore, Li symmetric cells stably run for 1000 h at 1 mA cm -2 and 1 mA h cm -2 and even survive for 380 h at an ultra-high capacity of 30 mA h cm -2 . With such a highly stable Li anode, LiFePO 4 cells operate steadily for 1600 and 1000 cycles at 1 and 5 C, respectively. High-loading LiCoO 2 cells also present excellent cycling stability and rate capability, proving the advantages of the protective layer in Li anode protection.
Direct carbon solid oxide fuel cells (DC-SOFCs), which can efficiently convert chemical energy of carbonaceous fuels into electricity, have recently gained much research attention as they offer an effective way to address future economic and environmental challenges. Herein, B-site Ti-substituted (PrBa)0.95Fe2–xTixO6−δ (PBFTx, x = 0–0.3) materials are synthesized via a sol–gel combustion method and evaluated as anode materials for DC-SOFCs. Ti doping enhances the phase structure stability of the material under a reducing atmosphere. X-ray diffraction, scanning electron microscopy, and transmission electron microscopy analyses demonstrate the exsolution of metallic Fe nanoparticles on the surface of the PBFTx perovskite lattice after the materials are treated under a reducing atmosphere, which can improve the catalytic performance of DC-SOFC anode. Among the Ti-doped samples (x = 0.1–0.3), PBFT0.2 shows the largest adsorption capacity for CO and the highest electrical conductivity in air. Using pure nano-activated carbon as a fuel, the single cell supported by La0.9Sr0.1Ga0.8Mg0.2O3 electrolyte with PBFT0.2 as an anode achieves the maximum power densities of 527, 281, and 146 mW·cm–2 at 800, 750, and 700 °C, respectively. The above excellent performance of PBFT0.2 indicates that it has great potential for application in DC-SOFC anode.
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