Irreparable Interphase Chemistry Degradation Induced by Temperature Pulse in Lithium-Ion Batteries

While it is widely recognized that the operating temperature significantly affects the energy density and cycle life of lithium-ion batteries, the consequence of electrode-electrolyte interphase chemistry to sudden environmental temperature changes remains inadequately understood. Here, we systematically investigate the effects of a temperature pulse (T pulse) on the electrochemical performance of LiNi_0.8Mn_0.1Co_0.1O₂ (NMC811) pouch full cells. By utilizing advanced characterization tools, such as time-of-flight secondary-ion mass spectrometry, we reveal that the T pulse can lead to an irreversible degradation of cathode-electrolyte interphase chemistry and architecture. Despite negligible immediate impacts on the solid-electrolyte interphase (SEI) on graphite anode, aggregated cathode-to-anode chemical crossover gradually degrades the SEI by catalyzing electrolyte reduction decomposition and inducing metallic dead Li formation because of insufficient cathode passivation after the T pulse. Consequently, pouch cells subjected to the T pulse show an inferior cycle stability to those free of the T pulse. This work unveils the effects of sudden temperature changes on the interphase chemistry and cell performance, emphasizing the importance of a proper temperature management in assessing performance.     

Highly Efficient Organosulfur and Lithium-Metal Hosts Enabled by C@Fe3N Sponge

Lithium-organosulfur (Li-OS) batteries, despite possessing high theoretical specific capacity, encounter a few practical challenges, including unsatisfactory lifespan and low active material utilization under realistic conditions. Here, diisoropyl xanthogen polysulfide (DIXPS) has been selected as a model organosulfur compound to investigate the practical feasibility of Li-OS batteries under realistic conditions. A well-designed freestanding carbon sponge decorated with Fe₃N nanoparticles (C@Fe₃N) is introduced into the Li-OS cells as a scaffold for both Li and DIXPS. The lithiophilic property of the C@Fe₃N host guides uniform lithium deposition at the anode, and the catalysis of the DIXPS conversion reaction promotes the kinetics at the cathode. Impressively, the synergistic effect of C@Fe₃N leads to an extremely stable cycling performance over 1 000 cycles in a Li-OS full cell under realistic conditions.     

Reactions of P(MeNCH2CH2)3N with primary,secondary, and tertiary alkyl halides: Evidence for a solvent-enhanced dehydrohalogenation

The reactions of P(MeNCH₂CH₂)₃N, 1, with Mel, EtI, EtBr, n-PrBr, n-BuI, i-PrBr, PhCH₂CHBrCH₃, MeCHBr(CH₂)₄Me, s-BuBr, and t-BuBr were studied. The reactions of the primary alkyl halides produced the corresponding phosphonium cationic compounds, whereas the secondary and tertiary halides underwent elimination to form the corresponding olefins and the protonated form of 1. Based on ¹H and ¹³C NMR studies, it appears that elimination is exclusively trans, favoring the Saytzeff product. It was also observed that this reaction is enhanced by the solvent CH₃CN. The X-ray crystal structure of [Me(I)] I is also reported, featuring a transannular distance of 2.773 Å (2) facilitated by a rather wide average equatorial MeN-P-NMe bond angle of 113.1 (2)°. © 1996 John Wiley & Sons, Inc.     

Realization of Z2 Topological Metal in Single-Crystalline Nickel Deficient NiV2Se4

Temperature-dependent electronic and magnetic properties are reported for nickel-deficient NiV₂Se₄. Single-crystal X-ray diffraction shows it to crystallize in the monoclinic Cr₃S₄ structure type with space group $I2/m$ and vacancies on the Ni site, resulting in the composition Ni_0.85V₂Se₄ in agreement with our electron-probe microanalysis. Structural distortions are not observed down to 1.5 K. Nevertheless, the electrical resistivity shows metallic behavior with a broad anomaly around 150–200 K that is also observed in the heat capacity data. This anomaly indicates a change of state of the material below 150 K. It is believed that this anomaly could be due to spin fluctuations or charge-density-wave fluctuations, where the lack of long-range order is caused by vacancies at the Ni site of Ni_0.85V₂Se₄. The non-linear temperature dependence of the resistivity as well as an enhanced value of the Sommerfeld coefficient $\gamma =104.0(1)$ mJ mol⁻¹ K⁻² suggest strong electron–electron correlations in this material. First-principles calculations performed for NiV₂Se₄, which are also applicable to Ni_0.85V₂Se₄, classify this material as a topological metal with $Z_2=(1;110)$ and coexisting electron and hole pockets at the Fermi level. The phonon spectrum lacks any soft phonon mode, consistent with the absence of periodic lattice distortion in the present experiments.     

Industrial cutting waste granite dust reinforced cardanol benzoxazine/epoxy resin hybrid composites for high-voltage electrical insulation applications

An attempt has been made to develop hybrid composites from benzoxazine monomer (C-ddm) hybridized with DGEBA epoxy resin (EP) and reinforced with varying weight percentages (20 wt%, 40 wt%, 60 wt%, 80 wt% and 100 wt%) of glycidoxypropyltrimethoxy- silane (GPTMS) functionalized granite dust (GD) obtained from industrial granite cutting and polishing process in order to utilize them for electrical insulation applications. The thermal stability of granite dust reinforced poly(EP-co-C-ddm) composites was studied by TGA analysis. Among the composites samples studied, 100 wt% GD reinforced poly(EP-co-C-ddm) composites possess better thermal stability than that of other neat matrices and composites. Among the composites prepared using varying weight percentages of functionalized GD reinforcement, it was observed that 80 wt% GD reinforced poly(EP-co-C-ddm) composites possesses better hydrophobic character than that of other neat matrices and composites. The value of LOI calculated for neat matrix (poly[EP-co-C-ddm]) and 20 wt%, 40 wt%, 60 wt%, 80 wt% and 100 wt% GD reinforced composites was found to be 22, 28, 34, 40, 43 and 45 respectively. The 80 wt% GD reinforced poly(EP-co-C-ddm) composites possess the higher values of tensile strength and flexural strength of 47 MPa and 140 MPa, respectively than those of their samples. The values of electrical surface resistivity and electrical volume resistivity of all the neat matrices and GD reinforced polybenzoxazine composites were found to be in the order of 10¹² and 10¹³ respectively. The values of dielectric strength obtained from break down voltage (BDV) for neat matrix [poly(EP-co-C-ddm)] and 20 wt%, 40 wt%, 60 wt%, 80 wt% and 100 wt% of GD reinforced poly(EP-co-C-ddm) composites are 15.0, 15.5, 16.5, 17.0, 17.0 and 17.0 kV/mm, respectively. Data obtained from thermal stability, hydrophobic behavior and dielectric studies it was inferred that the hybrid polymer composites developed in the present work can be conveniently used in the form insulators, sealants, adhesives and matrices where application demands at high-performance industrial and engineering applications.     

Facile synthesis of Mn-Ni bimetal organic framework decorated with amine as an electrode for a high-performance supercapacitor

Journal of Solid State Electrochemistry - In the recent years, the whole world is looking for better energy storage devices. Supercapacitors are among the most promising high-capacity...     

Static and Dynamic Magnetic Properties of a Co(II)-Complex with N2O2 Donor Set – A Theoretical and Experimental Study

A representative Co(II) based single ion magnet (SIM) with N₂O₂ donor set and distorted pseudo-tetrahedral geometry has been synthesized and characterized to study the atomic and electronic structure. DC magnetometry results have been evaluated by means of a phenomenological Hamiltonian approach regarding zero field splitting (ZFS) parameters and compared with results from ab-initio multi-reference CASSCF (complete active space self-consistent field) calculations and qualitative ligand field theory (AILFT). Profound investigation of spin-lattice relaxation with the variation of temperature (from 1.8 to about 8 K) and magnetic field (at 14 different fields from zero up to 1 T) have been performed based on AC magnetometry. Under an applied dc magnetic field, spin-lattice relaxation occurs via a direct process with T² temperature dependence due to limited heat transfer at very low temperature and above 5 K relaxation by an Orbach process with an energy barrier of ≈80 K dominates.