External-to-internal synergistic strategy to enable multi-scale stabilization of LiCoO_(2)at high-voltage

High-voltage LiCoO_(2)(LCO)offers a prelude to breaking the bottleneck of the energy density of lithium-ion batteries,however,LiCoO_(2)is subject to serious structural and interfacial degradation above voltages>4.55 V(vs.Li/Li^(+)).Herein,an in-situ Li_(6.25)La_(3)Zr_(2)A_(l0.25)O_(12)(LLZAO)layer is constructed on the LCO surface to achieve operating voltage at 4.6 V.The detailed characterizations(ex-situ XRD,ex-situ Raman,DFT,etc.)reveal that the LLZAO layer greatly enhances Li+conductivity attributed to the ionconducting layer on the surface/interface,and closely combines with LiCoO_(2)particle to ensure stable cathode/electrolyte interface,thus suppressing the highly reactive Co^(4+)and O^(-)triggered surface side reactions at high-voltage.Moreover,the introduction of La^(3+)/Zr^(4+)/Al^(3+)with a larger ionic radius(La^(3+)/Zr^(4+)are larger than Co^(3+))and weaker electronegativity(La/Zr/Al are weaker than Co)into Co^(3+)sites readjusts the electron cloud density between Co–O–Li,which reinforces the Co–O bond and widens the band-center gap of Co 3d and O 2p,thus restraining the detrimental phase transition(from H3 to H1-3 phase)and the formation of Co_(3)O_(4)spinel phase(attributed to lattice oxygen release),subsequently alleviating the particle cracking and structural collapse during repeated Li^(+)de/intercalation.Therefore,after 100 cycles at 3.0–4.6 V,LCO@1.0LLZAO exhibits a superior discharge capacity of 188.5 m A h g^(-1),with a capacity retention of 85.1%.The above research has brought about meaningful guidance for the evolution of cathode materials with high voltage.

Facile construction of a multilayered interface for a durable lithium‐rich cathode

Layered lithium-rich manganese-based oxide(LRMO)has the limitation of inevitable evolution of lattice oxygen release and layered structure transformation.Herein,a multilayer reconstruction strategy is applied to LRMO via facile pyrolysis of potassium Prussian blue.The multilayer interface is visually observed using an atomic-resolution scanning transmission electron microscope and a high-resolution transmission electron microscope.Combined with the electrochemical characterization,the redox of lattice oxygen is suppressed during the initial charging.In situ X-ray diffraction and the high-resolution transmission electron microscope demonstrate that the suppressed evolution of lattice oxygen eliminates the variation in the unit cell parameters during initial(de)lithiation,which further prevents lattice distortion during long cycling.As a result,the initial Coulombic efficiency of the modified LRMO is up to 87.31%,and the rate capacity and long-term cycle stability also improved considerably.In this work,a facile surface reconstruction strategy is used to suppress vigorous anionic redox,which is expected to stimulate material design in high-performance lithium ion batteries.

Chemical bonding of perovskite LaFeO_(3) with Li_(1.2)Mn_(0.6)Ni_(0.2)O_(2) to moderate anion redox for achieving high cycling stability

Oxygen anion redox reaction provides a high theoretical capacity for Li-rich manganese-based cathodes.However,irreversible surface oxygen release often results in further oxygen loss and exacerbates the decomposition of the electrolyte,which could reduce the capacity contribution from the anionic redox and produce more acidic substances to corrode the surface of the material.In this paper,the surface oxygen release is suppressed by moderating oxygen anion redox activity via constructing chemical bonds between M(M=Fe and La)in LaFeO_(3)and surface oxygen anions of Li_(1.2)Mn_(0.6)Ni_(0.2)O_(2).The constructed interface layer stabilizes the surface lattice oxygen and retards the electrolyte from being attacked by the nucleophilic oxygen generated in the process of oxygen release,as evidenced by Differential Electrochemical Mass Spectrometry(DEMS)and X-ray Photoelectron Spectroscopy(XPS)detections.Moreover,in the charge and discharge process,the formed FeF_(3),located at the cathode electrolyte interfacial layer,is conducive to the stability of the cathode surface.The modified Li_(1.2)Mn_(0.6)Ni_(0.2)O_(2)electrode with 3 wt%LaFeO_(13)exhibits a high specific capacity of 189.5 mA h g-at 1C(200 mA g^(-1))after 150 cycles with capacity retentions of 96.6%,and 112.6 mA h g^(-1)(84.7%)at 5C after 200 cycles higher than the pristine sample.This study provides a rational design chemical bonding method to suppress the oxygen release from the cathode surface and enhance cyclic stability.

Gas Generation Mechanism in Li-Metal Batteries

Gas generation induced by parasitic reactions in lithium-metal batteries(LMB)has been regarded as one of the fundamental barriers to the reversibility of this battery chemistry,which occurs via the complex interplays among electrolytes,cathode,anode,and the decomposition species that travel across the cell.In this work,a novel in situ differential electrochemical mass spectrometry is constructed to differentiate the speciation and source of each gas product generated either during cycling or during storage in the presence of cathode chemistries of varying structure and nickel contents.It unambiguously excludes the trace moisture in electrolyte as the major source of hydrogen and convincingly identifies the layer-structured NCM cathode material as the source of instability that releases active oxygen from the lattice at high voltages when NCM experiences H2→H3 phase transition,which in turn reacts with carbonate solvents,producing both CO_(2)and proton at the cathode side.Such proton in solvated state travels across the cell and becomes the main source for hydrogen generated at the anode side.Mechanisms are proposed to account for these irreversible reactions,and two electrolyte additives based on phosphate structure are adopted to mitigate the gas generation based on the understanding of the above decomposition chemistries.

All-in-one functional supramolecular nanoparticles based on pillar[5]arene for controlled generation,storage and release of singlet oxygen

The storage and controlled release of singlet oxygen(^(1)O_(2))have attracted increasing attention due to the wide application and microsecond lifetime of^(1)O_(2)in water.Herein we provide an integrated nanoplatform consisting of a diphenylanthracene derivative,a water-soluble pillar[5]arene and a photosensitizer tetrakis(4-hydroxyphenyl)porphyrin(TPP),that may provide the controlled generation,storage and release of singlet oxygen.We design a new diphenylanthracene derivative with two trimethylammonium bromide groups on both ends that can be well recognized by the pillar[5]arene.The formed nanocarriers can be used to load TPP through their supramolecular self-assembly.The resulting nanoparticles show good water-solubility and uniform spherical morphology.After laser irradiation(660 nm),the nanoparticles exhibit excellent ability for the generation and storage of^(1)O_(2).When the irradiated nanoparticles are heated above 80°C,^(1)O_(2)can be released from the system.Therefore,in this paper we pioneer the use of noncovalent interaction to integrate the diphenylanthracene derivatives and photosensitizers into one functional system,which provides a new strategy for the controlled generation,storage and release of singlet oxygen.We believe this groundbreaking strategy will have a great potential in providing necessary amounts of^(1)O_(2)for the photodynamic therapy of tumors in dark.

Enhancing the singlet oxygen capture and release rate of metal-organic frameworks through interpenetration tuning

Recognized as one of the important active species involved in varicus ractions,singlet oxygen(^(1)O_(2))shows potential applications in chemical.blological,and environmental related fields.However,the con-trolled capture and release of^(1)O_(2)are still facing huge challenges due to its short lifetime and high re-activity.Herein,a framework-interpenetration tuning strategy was applied on a metal-organic framework(MOF)that aiming to improve the capture and release rate of O.The porosity of the MOF was remark-ably enhanced with the structural evolution from seven-fold(termed NKM-181)to six-fold interpene-tration(termed NKM-182),and the active anthracene sites became much mare accessible.Such drastic process can be achieved as simple as exchanging the primitive MOF in selected solvent and occurred surprisingly as single-crystal to single-crystal transformation.Also,additionally owing to the unblocked regular channels,NKM-182 shown significantly improved^(1)O_(2)trapping and releasing rates compared to strates an unprecedented regulation of^(1)O_(2)capture and release that of in NKM-181.This work demon process,along with achieving the highest^(1)O_(2)capture and release rate among reported porous materi-als.furthermore.the obtalned endoperoxides with^(1)O_(2)loaded(termed EPO-NKM-181 and EPO-NKM-182)can be used as a high efficiency smart material for anti-fake application.

Injectable reactive oxygen and nitrogen species-controlling hydrogels for tissue regeneration:current status and future perspectives

The dual role of reactive oxygen and nitrogen species(RONS)in physiological and pathological processes in biological systems has been widely reported.It has been recently suggested that the regulation of RONS levels under physiological and pathological conditions is a potential therapy to promote health and treat diseases,respectively.Injectable hydrogels have been emerging as promising biomaterials for RONS-related biomedical applications owing to their excellent biocompatibility,three-dimensional and extracellular matrix-mimicking structures,tunable properties and easy functionalization.These hydrogels have been developed as advanced injectable platforms for locally generating or scavenging RONS,depending on the specific conditions of the target disease.In this review article,the design principles and mechanism by which RONS are generated/scavenged from hydrogels are outlined alongside a discussion of their in vitro and in vivo evaluations.Additionally,we highlight the advantages and recent developments of these injectable RONS-controlling hydrogels for regenerativemedicines and tissue engineering applications.

The Accounting for Carbon Sequence and Oxygen Release of Forest Resources and the Case Study

The paper reviewed the references of carbon sequence and oxygen release of forest resources. The dynastic physical accounting model is established, and benefit transfer model is adopted to calculate willing to pay for carbon sequence and oxygen. Benghe Forestry Farm of Linyi Prefecture of Shandong Province is selected as the case study area, the accounting result is presented in the paper.

Construction of bimetallic Pt-Pd/CeO_(2)-ZrO_(2)-La_(2)O_(3) catalysts with different Pt/Pd ratios and its structure-activity correlations for three-way catalytic performance

A series of Pt-Pd bimetallic catalysts supported on CeO_(2)-ZrO_(2)-La_(2)O_(3) mixed oxides were synthesized through the conventional impregnation method.Three-way catalytic performance evaluations along with detailed physio-chemical characterizations were carried out to establish possible structure-activity correlations.Results show that on the one hand,different Pt/Pd ratios can strongly affect the TWC behaviors of Pt-Pd/CZL catalysts by modulating the synergistic effect between Pt and Pd.On the other hand,higher Pt/Pd ratio also favors better dispersion of precious metals.Such improved precious metals(PM)dispersion can promote the metal-support interaction and increase the surface oxygen vacancies concentration,thereby raising the dynamic oxygen storage/release capacity,improving the redox ability as well as enha ncing the thermal stability of the Pt-Pd/CZL catalyst.Moreover,the stro ng metal-support interaction can augment surface oxygen vacancy concentration,thereby benefiting low temperature CO and NO reaction via augmented NOxadsorption and nitrate conversion.

Preparation of Fe_x Ce_(1-x) O_y solid solution and its application in Pd-only three-way catalysts

FeOx-CeO2 mixed oxides with increasing Fe/（Ce＋Fe） atomic ratio （1-20 mol%） were prepared by sol-gel method and characterized by X-ray powder diffraction （XRD）, Brunauer-Emrnett-Teller （BET） and Hydrogen temperature-programmed reduction （H2-TPR） techniques. The dynamic oxygen storage capacity （DOSC） was investigated by mass spectrometry with CO/O2 transient pulses. The powder XRD data following Rietveld refinement revealed that the solubility limit of iron oxides in the CeO2 was 5 mol% based on Fe/（Ce＋Fe）. The lattice parameters experienced a decrease followed by an increase due to the influence of the maximum solubility limit of iron oxides in the CeO2. TPR analysis revealed that Fe introduction into ceria strongly modified the textual and structural properties, which influenced the oxygen handling properties. DOSC results revealed that Ce-based materials containing Fe oxides with multiple valences contribute to the majority of DOSC. The kinetic analysis indicated that the calculated apparent kinetic parameters obey the compensation effect. The three-way catalytic performance for Pd-only catalysts based on the Fe doping support exhibited the redundant iron species separated out of the CeO2 and interacted with the ceria and Pd species on the surface, which seriously influenced the catalytic properties, especially after hydrothermal aging treatment.

结构设计稳定T2型富锂层状正极氧化物电极材料中的阴阳离子氧化还原活性

得益于阴离子氧化还原反应的引入,富锂材料具有较高的输出容量而被认为是下一代高能量密度电池正极材料的选择之一.然而氧相关的阴离子氧化还原反应的利用常常伴随着不可逆的晶格氧析出和严重的结构畸变.此外,由于复杂的阴阳离子氧化还原反应,使得富锂材料的电荷补偿机理也需要进一步澄清.本文报道了一种T2型Li_(0.72)[Li_(0.12)Ni_(0.36)Mn_(0.52)]O_(2)正极材料.研究发现,与其他典型的富锂层状正极不同,其具有不同于传统富锂材料的四面体碱金属配位环境与ABB′A′氧堆垛顺序.得益于其良好的结构稳定性和可逆的锂离子脱嵌过程,层状T2型正极材料具有良好的电化学稳定性,在较长的循环中具有较少的容量衰减和电压下降.研究人员通过详细的光谱表征,不仅标定了复杂的阴离子氧化还原行为,而且预估了相应的阳离子/阴离子氧化还原反应对应的电化学容量,这进一步阐明具有复杂氧化还原行为材料的电荷补偿机理.