High-temperature sodium–sulfur batteries operating at 300–350 °C have been commercially applied for large-scale energy storage and conversion. However, the safety concerns greatly inhibit their widespread adoption. Herein, we report a room-temperature sodium–sulfur battery with high electrochemical performances and enhanced safety by employing a “cocktail optimized” electrolyte system, containing propylene carbonate and fluoroethylene carbonate as co-solvents, highly concentrated sodium salt, and indium triiodide as an additive. As verified by first-principle calculation and experimental characterization, the fluoroethylene carbonate solvent and high salt concentration not only dramatically reduce the solubility of sodium polysulfides, but also construct a robust solid-electrolyte interface on the sodium anode upon cycling. Indium triiodide as redox mediator simultaneously increases the kinetic transformation of sodium sulfide on the cathode and forms a passivating indium layer on the anode to prevent it from polysulfide corrosion. The as-developed sodium–sulfur batteries deliver high capacity and long cycling stability.

The deployment of high-energy-density lithiummetal batteries has been greatly impeded by Li dendrite growth and safety concerns originating from flammable liquid electrolytes.H erein, we report as table quasi-solid-state Li metal battery with ad eep eutectic solvent (DES)-based self-healing polymer (DSP) electrolyte.T his electrolyte was fabricated in afacile manner by in situ copolymerization of 2-(3-(6-methyl-4-oxo-1,4-dihydropyrimidin-2-yl)ureido)ethyl methacrylate (UPyMA) and pentaerythritol tetraacrylate (PETEA) monomers in aD ES-based electrolyte containing fluoroethylene carbonate (FEC) as an additive.T he well-designed DSP electrolyte simultaneously possesses non-flammability,h igh ionic conductivity and electrochemical stability,a nd dendritefree Li plating. When applied in Li metal batteries with aLiMn 2 O 4 cathode,the DSP electrolyte effectively suppressed manganese dissolution from the cathode and enabled highcapacity and al ong lifespan at room and elevated temperatures.

The development of dual-ion sodium metal batteries (DISBs) with high output voltage and low cost is significantly hindered by dendritic sodium growth and severe electrolyte decomposition. In this work, we report a multifunctional gel polymer electrolyte with fluoroethylene carbonate co-solvent and 1,3propanesultone additive, which exhibits high oxidative stability, constructs stable protective layers on electrode surfaces, and enables uniform plating and intercalation of the cation or anion. The reversible capacity and cyclability of the as-developed DISB is thus significantly improved.

Topological Dirac semimetals (TDSs) represent a new state of quantum matter recently discovered that offers a platform for realizing many exotic physical phenomena. A TDS is characterized by the linear touching of bulk (conduction and valance) bands at discrete points in the momentum space (i.e. 3D Dirac points), such as in Na3Bi and Cd3As2. More recently, new types of Dirac semimetals with robust Dirac line-nodes (with non-trivial topology or near the critical point between topological phase transitions) have been proposed that extends the bulk linear touching from discrete points to 1D lines. In this work, using angle-resolved photoemission spectroscopy (ARPES), we explored the electronic structure of the non-symmorphic crystals MSiS (M=Hf, Zr). Remarkably, by mapping out the band structure in the full 3D Brillouin Zone (BZ), we observed two sets of Dirac line-nodes in parallel with the kz-axis and their dispersions. Interestingly, along directions other than the line-nodes in the 3D BZ, the bulk degeneracy is lifted by spinorbit coupling (SOC) in both compounds with larger magnitude in HfSiS. Our work not only experimentally confirms a new Dirac line-node semimetal family protected by nonsymmorphic symmetry, but also helps understanding and further exploring the exotic properties as well as practical applications of the MSiS family of compounds.

The stacking of complementary two-dimensional (2D) materials into hybrid architectures is desirable for batteries with enhanced capacity, fast charging, and long lifetime. However, the 2D heterostructures for energy storage are still underdeveloped, and some associated problems like low Coulombic efficiencies need to be tackled. Herein, we reported a phosphorene/MXene hybrid anode with an in situ formed fluorinated interphase for stable and fast sodium storage. The combination of phosphorene nanosheets with Ti 3 C 2 T x MXene not only facilitates the migration of both electrons and sodium cations but also alleviates structural expansion of phosphorene and thereby improves the cycling performance of the hybrid anode. X-ray photoelectron spectroscopy in-depth analysis reveals that the fluorine terminated MXene stabilize the solid electrolyte interphase by forming fluorine-rich compounds on the anode surface. Density functional theory calculations confirm that the sodium affinities and diffusion kinetics are significantly enhanced in the phosphorene/MXene heterostructure, particularly in the phosphorene/Ti 3 C 2 F 2 . As a result, the hybrid electrode achieved a high reversible capacity of 535 mAh g −1 at 0.1 A g −1 and superior cycling performance (343 mAh g −1 after 1000 cycles at 1 A g −1 with a capacity retention of 87%) in a fluorine-free carbonate electrolyte.

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The occurrence of osteoarthritis (OA) is highly associated with the reduced lubrication property of the joint, where a progressive and irreversible damage of the articular cartilage and consecutive inflammatory response dominate the mechanism. In this study, bioinspired by the super-lubrication property of cartilage and catecholamine chemistry of mussel, we successfully developed injectable hydrogel microspheres with enhanced lubrication and controllable drug release for OA treatment. Particularly, the lubricating microspheres (GelMA@DMA-MPC) were fabricated by dip coating a self-adhesive polymer (DMA-MPC, synthesized by free radical copolymerization) on superficial surface of photo-crosslinked methacrylate gelatin hydrogel microspheres (GelMA, prepared via microfluidic technology), and encapsulated with an anti-inflammatory drug of diclofenac sodium (DS) to achieve the dual-functional performance. The tribological test and drug release test showed the enhanced lubrication and sustained drug release of the GelMA@DMA-MPC microspheres. In addition, the functionalized microspheres were intra-articularly injected into the rat knee joint with an OA model, and the biological tests including qRT-PCR, immunofluorescence staining assay, X-ray radiography and histological staining assay all revealed that the biocompatible microspheres provided significant therapeutic effect against the development of OA. In summary, the injectable hydrogel microspheres developed herein greatly improved lubrication and achieved sustained local drug release, therefore representing a facile and promising technique for the treatment of OA.

Nonuniform local electric field and few nucleation sites on the reactive interface tend to cause detrimental lithium (Li) dendrites, which incur severe safety hazards and hamper the practical application of Li metal anodes in batteries. Herein, a carbon nanofiber (CNF) mat decorated with ultrafine titanium nitride (TiN) nanoparticles (CNF‐TiN) as both current collector and host material is reported for Li metal anodes. Uniform Li deposition is achieved by a synergetic effect of lithiophilic TiN and 3D CNF configuration with a highly conductive network. Theoretical calculations reveal that Li prefers to be adsorbed onto the TiN sheath with a low diffusion energy barrier, leading to controllable nucleation sites and dendrite‐free Li deposits. Moreover, the pseudocapacitive behavior of TiN identified through kinetics analysis is favorable for ultrafast Li+ storage and the charge transfer process, especially under a high plating/stripping rate. The CNF‐TiN‐modified Li anodes deliver lower nucleation overpotential for Li plating and superior electrochemical performance under a large current density (200 cycles at 3 mA cm−2) and high capacity (100 cycles with 6 mAh cm−2), as well as a long‐running lifespan (>600 h). The CNF‐TiN‐based full cells using lithium iron phosphate and sulfur cathodes exhibit excellent cycling stability.