LiNi_0.8Co_0.1Mn_0.1O₂ (NCM811) is considered as a promising cathode for high-energy-density solid-sate Li metal battery for its high theoretical capacity. However, the high oxidizability and structural instability during charge limit its practical applications. In this work, 1% (in mass) of nanosized Li_1.3Al_0.3Ti_1.7(PO₄)₃ (LATP) was coated on NCM811 to enhance its electrochemical stability with a ceramic/polymer composite electrolyte. A robust, ultrathin (11 μm) composite electrolyte film was prepared by combining poly(vinylidene fluoride) (PVDF) with polyethylene oxide (PEO)-Li_6.5La₃Zr_1.5Ta_0.5O₁₂ (LLZTO). An in-situ polymerization process was used to enhance the interface between the PVDF/PEO-LLZTO (PPL) composite electrolyte and the LATP-coated NCM811 (LATP-NCM811). Coin-type Li|LATP-NCM811 cell with the PPL electrolyte exhibits stable cycling with an 81% capacity retention after 100 cycles at 0.5 C. Pouch-type cell was also fabricated, which can be stably cycled for 70 cycles at 0.5 C/1.0 C (80% retention), and withstand abuse tests of bending, cutting and nail penetration. This work provides an applicable method to fabricate solid-state Li metal batteries with high performance.

Lithium metal batteries are regarded as promising alternatives to lithium ion batteries due to their high specific capacity. However, lithium dendrite growth during cycling causes safety problem and rapid capacity loss. Here, we report a composite Li anode composed (LYF) of metallic Li and trace amounts (1–2 wt%) of two-dimensional YF_δ. The lithiophilic nature of YF_δ enables its homogeneous dispersion in metallic lithium. The LYF electrode exhibits lower resistance, higher chemical and mechanical stability, and longer cycle life compared to bare Li electrode due to uniform Li stripping and plating with YF_δ incorporation, which was confirmed by in-situ optical microscope observation. X-ray photoelectron spectroscopy reveals that LiF can in-situ form on the LYF electrode with reactions between Li and YF_δ during cycling. The spontaneous reactions are clarified by density functional theory calculations. A quasi-solid-state cell with LYF anode, LiFePO₄ cathode and cathode-supported solid electrolyte layer has been constructed with a soft interface constructed between Li anode and solid electrolyte by in-situ thermal polymerization. The cell shows a high initial discharge capacity of 147 mAh g⁻¹ at 0.5 C at 60 ℃ and sustains a stable cycling over 50 cycles with the in-situ formed LiF-rich layer and soft interface.

(Bi, Sb)₂(Te,Se)₃ alloys are widely used commercial thermoelectric (TE) materials for solid-state refrigeration around room temperature. The composition-induced structural phase transition could be realized by varying the compositions in these alloys, which may largely alter the electronic structure and phonon dispersion. Among them, the Se-alloyed Sb₂Te₃ accompanied with structural transition is seldom reported. Herein, the interrelations of Se-alloying induced changes in structural phase transition, band structure and TE properties of p-type zone-melted Sb₂Te_3-xSe_x (x = 1.5–2.4) alloys near phase transition boundary are systematically investigated. The results demonstrate that Sb₂Te_3-xSe_x shows a structural transition from a rhombohedral phase to mixed structure at x = 2.0. The carrier concentration and bandgap at room temperature of Sb₂Te_3-xSe_x (x = 1.5–2.4) constantly decrease with increasing Se contents x. The zT peak of the Sb₂TeSe₂ matrix is improved and shifted to higher temperature by optimizing carrier concentration via Ag doping. A maximum zT of ~0.4 is obtained at 680 K in Sb_1.97Ag_0.03TeSe₂ alloy, about 100% enhancement compared with the undoped sample.