Tailoring Na+ Solvation Environment and Electrode-Electrolyte Interphases with Sn(OTf)2 Additive in Non-flammable Phosphate Electrolytes towards Safe and Efficient Na-S Batteries.

Room-temperature sodium-sulfur (RT Na-S) batteries are promising for low-cost and large-scale energy storage applications. However, these batteries are plagued by safety concerns due to the highly flammable nature of conventional electrolytes. Although non-flammable electrolytes eliminate the risk of fire, they often result in compromised battery performance due to poor compatibility with sodium metal anode and sulfur cathode. Herein, we develop an additive of tin trifluoromethanesulfonate (Sn(OTf)2 ) in non-flammable phosphate electrolytes to improve the cycling stability of RT Na-S batteries via modulating the Na+ solvation environment and interface chemistry. The additive reduces the Na+ desolvation energy and enhances the electrolyte stability. Moreover, it facilitates the construction of Na-Sn alloy-based anode solid electrolyte interphase (SEI) and cathode electrolyte interphase (CEI). These interphases help to suppress the growth of Na dendrites and the dissolution/shuttling of sodium polysulfides (NaPSs), resulting in improved reversible capacity. Specifically, the Na-S battery with the designed electrolyte boosts the capacity from 322 to 906 mAh g-1 at 0.5 A g-1 . This study provides valuable insights for the development of safe and high-performance electrolytes in RT Na-S batteries.

Boosting the "Solid-Liquid-Solid" Conversion Reaction via Bifunctional Carbonate-Based Electrolyte for Ultra-long-life Potassium-Sulfur Batteries.

Potassium-sulfur (K-S) batteries have attracted wide attention owing to their high theoretical energy density and low cost. However, the intractable shuttle effect of K polysulfides results in poor cyclability of K-S batteries, which severely limits their practical application. Herein, a bifunctional concentrated electrolyte (3 mol L-1 potassium bis(trifluoromethanesulfonyl)imide in ethylene carbonate (EC)) with high ionic conductivity and low viscosity is developed to regulate the dissolution behavior of polysulfides and induce uniform K deposition. The organic groups in the cathode electrolyte interphase layer derived from EC can effectively block the polysulfide shuttle and realize a "solid-liquid-solid" reaction mechanism. The KF-riched solid-electrolyte interphase inhibits K dendrite growth during cycling. As a result, the achieved K-S batteries display a high reversible capacity of 654 mAh g-1 at 0.5 A g-1 after 800 cycles and a long lifespan over 2000 cycles at 1 A g-1 .

Neuro-safety science: an emerging discipline to reveal the neural mechanisms of safety problems.

At present, the research of safety science discipline is limited to the level of describing psychology and behaviors, because the cognitive neural mechanisms behind them are unknown. This paper introduces an emerging interdiscipline, namely neuro-safety science, which uses the neuroscientific methods to investigate the neural systems behind safely relevant behaviors. Qualitative methods such as literature review method and theoretical model construction method were adopted for this study. Based on the background of neuro-safety science, the definition of neuro-safety science was defined, its connotation was analyzed, and the research contents from two aspects of theoretical research and practical application research were proposed. Methodology system including research principles, research routes, research procedure and research methods, and the paradigm system of neuro-safety science were put forward. At last, the application research on neuro-safety science was forecasted. This paper opens up a new research perspective for the research of safety science, and provide guidance and reference to develop neuro-safety science.

Optimizing the Fermi Level of a 3D Current Collector with Ni3 S2 /Ni3 P Heterostructure for Dendrite-Free Sodium-Metal Batteries.

Rechargeable sodium-metal batteries (RSMBs) with high energy density and low cost are attracting extensive attention as promising energy-storage technologies. However, the poor cyclability and safety issues caused by unstable solid electrolyte interphase (SEI) structure and dendrite issues limit their practical application. Herein, it is theoretically predicted that constructing the Ni3 S2 /Ni3 P heterostructure with high work function can lower the Fermi energy level, and therefore effectively suppressing continuous electrolyte decomposition derived from the electron-tunneling effect after long-term sodiation process. Furthermore, the Ni3 S2 /Ni3 P heterostructure on 3D porous nickel foam (Ni3 S2 /Ni3 P@NF) is experimentally fabricated as an advanced Na-anode current collector. The seamless Ni3 S2 /Ni3 P heterostructure not only offers abundant active sites to induce uniform Na+ deposition and enhance ion-transport kinetics, but also facilitates the formation of stable SEI for dendrite-free sodium anode, which are confirmed by cryogenic components transmission electron microscopy tests and in situ spectroscopy characterization. As a result, the Na-composite anode (Ni3 S2 /Ni3 P@NF@Na) delivers stable plating/stripping process of 5000 h and high average Coulombic efficiency of 99.7% over 2500 cycles. More impressively, the assembled sodium-ion full cell displays ultralong cycle life of 10 000 cycles at 20 C. The strategy of stabilizing the sodium-metal anode gives fundamental insight into the potential construction of advanced RSMBs.

Revisiting the Role of Physical Confinement and Chemical Regulation of 3D Hosts for Dendrite-Free Li Metal Anode.

Lithium metal anode has been demonstrated as the most promising anode for lithium batteries because of its high theoretical capacity, but infinite volume change and dendritic growth during Li electrodeposition have prevented its practical applications. Both physical morphology confinement and chemical adsorption/diffusion regulation are two crucial approaches to designing lithiophilic materials to alleviate dendrite of Li metal anode. However, their roles in suppressing dendrite growth for long-life Li anode are not fully understood yet. Herein, three different Ni-based nanosheet arrays (NiO-NS, Ni3N-NS, and Ni5P4-NS) on carbon cloth as proof-of-concept lithiophilic frameworks are proposed for Li metal anodes. The two-dimensional nanoarray is more promising to facilitate uniform Li+ flow and electric field. Compared with the NiO-NS and the Ni5P4-NS, the Ni3N-NS on carbon cloth after reacting with molten Li (Li-Ni/Li3N-NS@CC) can afford the strongest adsorption to Li+ and the most rapid Li+ diffusion path. Therefore, the Li-Ni/Li3N-NS@CC electrode realizes the lowest overpotential and the most excellent electrochemical performance (60 mA cm-2 and 60 mAh cm-2 for 1000 h). Furthermore, a remarkable full battery (LiFePO4||Li-Ni/Li3N-NS@CC) reaches 300 cycles at 2C. This research provides valuable insight into designing dendrite-free alkali metal batteries.

RuO2 Particles Anchored on Brush-Like 3D Carbon Cloth Guide Homogenous Li/Na Nucleation Framework for Stable Li/Na Anode.

Lithium (sodium)-metal batteries are the most promising batteries for next-generation electrical energy storage due to their high volumetric energy density and gravimetric energy density. However, their applications have been prevented by uncontrollable dendrite growth and large volume expansion during the stripping/plating process. To address this issue, the key strategy is to realize uniform lithium (sodium) deposition during the stripping/plating process. Herein, a thin lithiophilic layer consisting of RuO2 particles anchored on brush-like 3D carbon cloth (RuO2 @CC) is prepared by a simple solution-based method. After infusion of Li, the RuO2 @CC transfers to Li-Ru@CC. Ru nanoparticles not only play a role in leading Li+ (Na+ ) to plate on the 3D carbon framework, but also lower local current density because of the good electrical conductivity. Furthermore, density functional theory calculations demonstrate that Ru metal, the reaction product of alkali metal and Ru, can lead Li+ to plate evenly around carbon fiber owing to the strong binding energy with Li+ . The Li-Ru@CC anode shows ultralong cycle life (1500 h at 5 mA cm-2 ). The full cell of Li-Ru@CC|LiFePO4 exhibits lower polarization (90% capacity retention after 650 cycles). In addition, sodium metal batteries based on Na-Ru@CC anodes can achieve similar improvement.

Three-Dimensional Ordered Macroporous Metal-Organic Framework Single Crystal-Derived Nitrogen-Doped Hierarchical Porous Carbon for High-Performance Potassium-Ion Batteries.

The biggest challenge of potassium-ion batteries (KIBs) application is to develop high-performance electrode materials to accommodate the potassium ions large size. Herein, by rational design, we carbonize three-dimensional (3D) ordered macroporous ZIF-8 to fabricate 3D interconnected nitrogen-doped hierarchical porous carbon (N-HPC) that shows excellent rate performance (94 mAh g-1 at 10.0 A g-1), unprecedented cycle stability (157 mA g-1 after 12000 cycles at 2.0 A g-1), and superior reversible capacity (292 mAh g-1 at 0.1 A g-1). The 3D hierarchical porous structure diminishes the diffusion distance for both ions/electrons, while N-doping improves the reactivity and electronic conductivity via producing more defects. In addition, the bicontinuous structure possesses a large specific surface area, decreasing the current density, again improving the rate performance. In situ Raman spectra analysis confirms the potassiation and depotassiation in the N-HPC are highly reversible processes. The galvanostatic intermittent titration measurement and first-principles calculations reveal that the interconnected macropores are more beneficial to the diffusion of the K+. This 3D interpenetrating structure demonstrates a superiority for energy storage applications.

Regulating Lithium Nucleation via CNTs Modifying Carbon Cloth Film for Stable Li Metal Anode.

Li metal is demonstrated as one of the most promising anode materials for high energy density batteries. However, uncontrollable Li dendrite growth and repeated growth of solid electrolyte interface during the charge/discharge process lead to safety issues and capacity decay, preventing its practical application. To address these issues, an effective strategy is to realize uniform Li nucleation. Here, a stable lithium-scaffold composite electrode (CC/CNT@Li) is designed by melting of lithium metal into 3D interconnected lithiophilic carbon nanotube (CNT) on a porous carbon cloth (CC). The 3D interconnected CNTs successfully change the lithiophobic CC into lithiophilic nature, reducing the polarization of the electrode, ensuring homogenous Li nucleation and continuous smooth Li plating. The CNTs on the surface of CC provide adequate Li nucleation sites and reduce the areal current density to avoid Li dendrite growth. The 3D porous structure of CC/CNT offers enough free room for buffering the huge volume change during Li plating/stripping. The CC/CNT@Li composite anode exhibits dendrite-free morphology and superior cycling performances over 500 h with low voltage hysteresis of 18, 23, and 71 mV at the current density of 1, 2, and 5 mA cm-2 , respectively.

CNT Interwoven Nitrogen and Oxygen Dual-Doped Porous Carbon Nanosheets as Free-Standing Electrodes for High-Performance Na-Se and K-Se Flexible Batteries.

Na-Se and K-Se batteries are attractive as a stationary energy storage system because of much abundant resources of Na and K in the Earth's crust. As the alloy-type Se has a severe pulverization issue, one critical challenge to develop advanced Na-Se and K-Se batteries is to explore a highly efficient and stable Se-based cathode. Herein, a flexible free-standing Se/carbon composite film is prepared by encapsulation of Se into a carbon nanotube (CNT) interwoven N,O dual-doped porous carbon nanosheet (Se@NOPC-CNT). The 3D interconnected CNT uniformly wrapped on the N,O dual-doped porous carbon skeletons improves the flexibility and offers an interconnected conductive pathway for rapid ionic/electronic transport. In addition, the N,O dual-doping significantly enhances the chemical affinity and adhesion between Nax Se/Kx Se (0 < x ≤ 2) and porous carbon, which is confirmed by density functional theory calculation. When used as the cathode in Na-Se batteries, the Se@NOPC-CNT delivers a remarkable reversible capacity of 400 mA h g-1 at 1 A g-1 after 2000 cycles with a 0.008% capacity decay per cycle. For K-Se batteries, it also exhibits an excellent cycling stability (335 mA h g-1 after 700 cycles at 0.8 A g-1 ). This unique design may open an avenue for practical application of flexible Na-Se and K-Se batteries.