Investigation of Li-ion transport in Li7P3S11 and solid-state lithium batteries

The high Li-ion conductivity of the Li7P3S11 sulfide-based solid electrolyte makes it a promising candidate for all-solid-state lithium batteries. The Li-ion transport over electrode-electrolyte and electrolyteelectrolyte interfaces, vital for the performance of solid-state batteries, is investigated by impedance spectroscopy and solid-state NMR experiments. An all-solid-state Li-ion battery is assembled with the Li7P3S11 electrolyte, nano-Li2S cathode and Li-In foil anode, showing a relatively large initial discharge capacity of 1139.5 m Ah/g at a current density of 0.064 m A/cm^ 2 retaining 850.0 m Ah/g after 30 cycles. Electrochemical impedance spectroscopy suggests that the decrease in capacity over cycling is due to the increased interfacial resistance between the electrode and the electrolyte. 1D exchange ^7Li NMR quantifies the interfacial Li-ion transport between the uncycled electrode and the electrolyte, resulting in a diffusion coefficient of 1.70(3) ×10^-14cm^2/s at 333 K and an energy barrier of 0.132 e V for the Li-ion transport between Li2S cathode and Li7P3S11 electrolyte. This indicates that the barrier for Li-ion transport over the electrode-electrolyte interface is small. However, the small diffusion coefficient for Li-ion diffusion between the Li2S and the Li7P3S11 suggests that these contact interfaces between electrode and electrolyte are relatively scarce, challenging the performance of these solid-state batteries.

Organochlorides Mediate Oxidation Reactions Induced by Low Dose Ionizing Radiation

The controlled release of drugs using local ionizing radiation presents a promising approach for targeted cancer treatment,particularly when applied in concurrent radio-chemotherapy.In these approaches,radiation-generated reactive species often play an important role.However,the reactive species that can be used to trigger release have low yield and lack selectivity.Here,we demonstrate the generation of highly oxidative species when aqueous solutions containing low concentrations of organochlorides(such as chloroform)are irradiated with ionizing radiation at therapeutically relevant doses.These reactive species were identified as peroxyl radicals,which formed in a reaction cascade between organochlorides and aqueous electrons.We employed stilbene-based probes to investigate the oxidation process,showing double bond oxidation and cleavage.To translate this reactivity into a radiation-sensitive material,we synthesized a micelle-forming amphiphilic block copolymer that has stilbene as the linker between two blocks.Upon exposure to ionizing radiation,the oxidation of stilbene led to the cleavage of the polymer,which induces the dissociation of the block-copolymer micelles and the release of loaded drugs.

Thermodynamics of multi-sublattice battery active materials: from an extended regular solution theory to a phase-field model of LiMn_(y)Fe_(1-y)PO_(4)

Phase separation during the lithiation of redox-active materials is a critical factor affecting battery performance,including energy density,charging rates,and cycle life.Accurate physical descriptions of these materials are necessary for understanding underlying lithiation mechanisms,performance limitations,and optimizing energy storage devices.This work presents an extended regular solution model that captures mutual interactions between sublattices of multi-sublattice battery materials,typically synthesized by metal substitution.We apply the model to phospho-olivine materials and demonstrate its quantitative accuracy in predicting the composition-dependent redox shift of the plateaus of LiMn_(y)Fe_(1-y)PO_(4)(LFMP),LiCo_(y)Fe_(1-y)PO_(4)(LFCP),LiCo_(x)Mn_(y)Fe_(1-y)PO_(4)(LFMCP),as well as their phase separation behavior.Furthermore,we develop a phase-field model of LFMP that consistently matches experimental data and identifies LiMn0.4Fe0.6PO4 as a superior composition that favors a solid solution phase transition,making it ideal for high-power applications.

Overview of magnetoelastic coupling in (Mn, Fe)2(P, Si)-type magnetocaloric materials

（MnFe）2（P, Si）-type compounds are, to date, one of the best candidates for magnetic refrigeration and energy conversion applications due to the combination of giant magnetocaloric effect （MCE）, tunable working temperature range and low material cost. The giant MCE in the （Mn, Fe）2（P, Si）-type compounds originates from strong mag- netoelastic coupling, where the lattice degrees of freedom and spin degrees of freedom are efficiently coupled. The tunability of the phase transition, in terms of the critical temperature and the character of the phase transition, is essentially attributed to the changes in the magnetoelastic coupling in the （Mn, Fe）2（P, Si）-type compounds. In this review, not only the fundamentals of the magnetoelastic coupling but also the related practical aspects such as magnetocaloric performance, hysteresis issue and mechanical stability are discussed for the （Mn, Fe）2（P, Si）- type compounds. Additionally, some future fundamental studies on the MCE as well as possible ways of solving the hysteresis and fracture issues are proposed.

Enhanced reversibility of the magnetoelastic transition in(Mn,Fe)2(P,Si)alloys via minimizing the transition-induced elastic strain energy

Magnetocaloric materials undergoing reversible phase transitions are highly desirable for magnetic refrigeration applications.(Mn,Fe)_(2)(P,Si)alloys exhibit a giant magnetocaloric effect accompanied by a magnetoelastic transition,while the noticeable irreversibility causes drastic degradation of the magnetocaloric properties during consecutive cooling cycles.In the present work,we performed a comprehensive study on the magnetoelastic transition of the(Mn,Fe)_(2)(P,Si)alloys by high-resolution transmission electron microscopy,in situ field-and temperature-dependent neutron powder diffraction as well as density functional theory calculations(DFT).We found a generalized relationship between the thermal hysteresis and the transition-induced elastic strain energy for the(Mn,Fe)_(2)(P,Si)family.The thermal hysteresis was greatly reduced from 11 to 1 K by a mere 4 at.%substitution of Fe by Mo in the Mn_(1.15)Fe_(0.80)P_(0.45)Si_(0.55)alloy.This reduction is found to be due to a strong reduction in the transition-induced elastic strain energy.The significantly enhanced reversibility of the magnetoelastic transition leads to a remarkable improvement of the reversible magnetocaloric properties,compared to the parent alloy.Based on the DFT calculations and the neutron diffraction experiments,we also elucidated the underlying mechanism of the tunable transition temperature for the(Mn,Fe)_(2)(P,Si)family,which can essentially be attributed to the strong competition between the covalent bonding and the ferromagnetic exchange coupling.The present work provides not only a new strategy to improve the reversibility of a first-order magnetic transition but also essential insight into the electron-spin-lattice coupling in giant magnetocaloric materials.

Room temperature synthesis of perylene diimides facilitated by high amic acid solubility

A novel protocol for the synthesis of perylene diimides(PDIs),by reacting perylene dianhydride(PDA)with aliphatic amines is reported.Full conversions were obtained at temperatures between 20 and 60℃,using DBU as the base in DMF or DMSO.A“green”synthesis of PDIs,that runs at higher temperatures,was developed using K_(2)CO_(3) in DMSO.

国产RPV钢铁离子辐照脆化行为的正电子湮灭研究

选取服役于我国高温气冷示范电站的反应堆压力容器(reactor pressure vessel,RPV)钢A508-3和纯Fe,采用3 Me V铁离子进行高温(250℃)与室温(约25℃)辐照,辐照损伤分别达0.1、0.5和1.0 dpa,对样品分别进行正电子湮灭和纳米压痕硬度研究。结果表明,辐照会使材料内部产生缺陷,这种缺陷以空位型缺陷和溶质原子团簇缺陷为主。且高温辐照产生的缺陷密度低于室温辐照,其中高温的退火效应使材料内部缺陷发生一定程度的回复。辐照后RPV钢和纯Fe都产生了一定程度的硬化,硬化程度随辐照损伤的增加而增高。对于RPV钢,高温辐照比室温辐照使材料内部产生更少的空位型缺陷和更多的溶质原子团簇型缺陷,因而RPV钢的辐照硬化可能主要是由溶质原子团簇型缺陷引起的。

Towards high performance cathodes for Na-ion batteries

The efficient and high energy storage in rechargeable lithium batteries has enabled portable electronic equipment,the demands on which are ever increasing as it also appears to be the technology of choice for electrical vehicles.Additionally,rechargeable lithium batteries appear to be suitable technology to stabilize the electrical grid and to lift the intermittency of renewable energy on a daily basis.Although lithium is relatively abundant in the Earth’s crust,