Catalytically Induced Robust Inorganic-Rich Cathode Electrolyte Interphase for 4.5 V Li||NCM622 Batteries

Tailoring inorganic components of cathode electrolyte interphase (CEI) and solid electrolyte interphase (SEI) is critical to improving the cycling performance of lithium metal batteries. However, it is challenging due to complicated electrolyte reactions on cathode/anode surfaces. Herein, the species and inorganic component content of the CEI/SEI is enriched with an objectively gradient distribution through employing pentafluorophenyl 4-nitrobenzenesulfonate (PFBNBS) as electrolyte additive guided by engineering bond order with functional groups. In addition, a catalytic effect of LiNi_0.6Mn_0.2Co_0.2O₂ (NCM622) cathode is proposed on the decomposition of PFBNBS. PFBNBS with lower highest occupied molecular orbital can be preferentially oxidized on the NCM622 surface with the help of the catalytic effect to induce an inorganic-rich CEI for superior electrochemical performance at high voltage. Moreover, PFBNBS can be reduced on the Li surface due to its lower lowest unoccupied molecular orbital , increasing inorganic moieties in SEI for inhibiting Li dendrite generation. Thus, 4.5 V Li||NCM622 batteries with such electrolyte can retain 70.4% of initial capacity after 500 cycles at 0.2 C, which is attributed to the protective effect of the excellent CEI on NCM622 and the inhibitory effect of its derived CEI/SEI on continuous electrolyte decomposition.     

A Materials Perspective on Direct Recycling of Lithium-Ion Batteries: Principles,Challenges and Opportunities

As the dominant means of energy storage technology today, the widespread deployment of lithium-ion batteries (LIBs) would inevitably generate countless spent batteries at their end of life. From the perspectives of environmental protection and resource sustainability, recycling is a necessary strategy to manage end-of-life LIBs. Compared with traditional hydrometallurgical and pyrometallurgical recycling methods, the emerging direct recycling technology, rejuvenating spent electrode materials via a non-destructive way, has attracted rising attention due to its energy efficient processes along with increased economic return and reduced CO₂ footprint. This review investigates the state-of-the-art direct recycling technologies based on effective relithiation through solid-state, aqueous, eutectic solution and ionic liquid mediums and thoroughly discusses the underlying regeneration mechanism of each method regarding different battery chemistries. It is concluded that direct regeneration can be a more energy-efficient, cost-effective, and sustainable way to recycle spent LIBs compared with traditional approaches. Additionally, it is also identified that the direct recycling technology is still in its infancy with several fundamental and technological hurdles such as efficient separation, binder removal and electrolyte recovery. In addressing these remaining challenges, this review proposes an outlook on potential technical avenues to accelerate the development of direct recycling toward industrial applications.     

Tetrabutylammonium Bromide Functionalized Ti3C2Tx MXene as Versatile Cathode Buffer Layer for Efficient and Stable Inverted Perovskite Solar Cells

2D Ti₃C₂T_x MXene, possessing facile preparation, high electrical conductivity, flexibility, and solution processability, shows good application potential for enhancing device performance of perovskite solar cells (PVSCs). In this study, tetrabutylammonium bromide functionalized Ti₃C₂T_x (TBAB-Ti₃C₂T_x) is developed as cathode buffer layer (CBL) to regulate the PCBM/Ag cathode interfacial property for the first time. By virtue of the charge transfer from TBAB to Ti₃C₂T_x demonstrated by electron paramagnetic resonance and density functional theory, the TBAB-Ti₃C₂T_x CBL with high electrical conductivity exhibits significantly reduced work function of 3.9 eV, which enables optimization of energy level alignment and enhancement of charge extraction. Moreover, the TBAB-Ti₃C₂T_x CBL can effectively inhibit the migration of iodine ions from perovskite layer to Ag cathode, which synergistically suppresses defect states and reduce charge recombination. Consequently, utilizing MAPbI₃ perovskite without post-treatment, the TBAB-Ti₃C₂T_x based device exhibits a dramatically improved power conversion efficiency of 21.65% with significantly improved operational stability, which is one of the best efficiencies reported for the devices based on MAPbI₃/PCBM with different CBLs. These results indicate that TBAB-Ti₃C₂T_x shall be a promising CBL for high-performance inverted PVSCs and inspire the further applications of quaternary ammonium functionalized MXenes in PVSCs.     

MoS2/C纳米复合材料的合成及其电化学性能研究

理论比能量高达2 600 Wh/kg的锂硫电池已经成为锂电池研究热点,然而硫导电性不好、穿梭效应和锂化体积效应较大等问题阻碍了锂硫电池的产业化。将无定型多孔碳材料的高导电性和极性MoS₂的固硫作用相结合改善锂硫电池的电化学性能。所得的S@MoS₂/C在0.05 C和2 C电流密度下的放电比容量分别为1 507和406.3 mAh/g,比S@MoS₂在相同电流密度下的放电比容量（1 400和345.7 mAh/g）更高。在循环性能测试中,S@MoS₂/C容量保持率为46.9%,要高于S@MoS₂（39.1%）。因此,MoS₂/C复合材料作为硫载体可以显著改善锂硫电池性能。     

Study of tool trajectory in blisk channel ECM with spiral feeding

Electrochemical machining (ECM) plays an important role in blisk manufacturing. There are two steps in blisk ECM: machining of channels and precise shaping of blade profiles. In channel machining, channels are machined in the workpiece with allowance left to the following process. Therefore, the main aim of channel machining with ECM is to improve the allowance distribution. With this aim, a new ECM method for blisk channels, spiral feeding ECM, is developed in which the cathode feeds from blade tip to hub along with rotation motion around its axis. Through this combined motion, twisted channels are produced in the workpiece. The relationship between feed position and rotation angle is presented in the form of a mathematical model. Experiments with a feed rate of 1 mm/min confirm that spiral feeding ECM is feasible and efficient. Compared with radial ECM, the allowance differences in blank back and blank basin decrease by 32.7% and 33.6%, respectively. The surface roughnesses Ra in blank back, blank basin, and hub are 0.358, 0.308, and 0.102 µm, respectively. Thus, the allowance distribution is improved to be more uniform considerably and the surface quality is relatively high.     

High Rate,Long Lifespan LiV3O8 Nanorods as a Cathode Material for Lithium‐Ion Batteries

LiV₃O₈ nanorods with controlled size are successfully synthesized using a nonionic triblock surfactant Pluronic‐F127 as the structure directing agent. X‐ray diffraction, scanning electron microscopy, and transmission electron microscopy techniques are used to characterize the samples. It is observed that the nanorods with a length of 4–8 µm and diameter of 0.5–1.0 µm distribute uniformly. The resultant LiV₃O₈ nanorods show much better performance as cathode materials in lithium‐ion batteries than normal LiV₃O₈ nanoparticles, which is associated with the their unique micro–nano‐like structure that can not only facilitate fast lithium ion transport, but also withstand erosion from electrolytes. The high discharge capacity (292.0 mAh g^?1 at 100 mA g^?1), high rate capability (138.4 mAh g^?1 at 6.4 A g^?1), and long lifespan (capacity retention of 80.5% after 500 cycles) suggest the potential use of LiV₃O₈ nanorods as alternative cathode materials for high‐power and long‐life lithium ion batteries. In particular, the synthetic strategy may open new routes toward the facile fabrication of nanostructured vanadium‐based compounds for energy storage applications.     

Spinel-layered integrate structured nanorods with both high capacity and superior high-rate capability as cathode material for lithium-ion batteries

Spinel phase LiMn2O4 was successfully embedded into monoclinic phase layeredstructured Li2MrnO3 nanorods,and these spinel-layered integrate structured nanorods showed both high capacities and superior high-rate capabilities as cathode material for lithium-ion batteries (LIBs).Pristine Li2MnO3 nanorods were synthesized by a simple rheological phase method using α-MnO2 nanowires as precursors.The spinel-layered integrate structured nanorods were fabricated by a facile partial reduction reaction using stearic acid as the reductant.Both structural characterizations and electrochemical properties of the integrate structured nanorods verified that LiMn2O4 nanodomains were embedded inside the pristine Li2MnO3 nanorods.When used as cathode materials for LIBs,the spinel-layered integrate structured Li2MnO3 nanorods (SL-Li2MnO3) showed much better performances than the pristine layered-structured Li2MnO3 nanorods (L-Li2MnO3).When charge-discharged at 20 mA·g-1 in a voltage window of 2.0-4.8 V,the SL-Li2MnO3 showed discharge capadties of 272.3 and 228.4 mAh.g-1 in the first and the 60th cycles,respectively,with capacity retention of 83.8％.The SL-Li2MnO3 also showed superior high-rate performances.When cycled at rates of 1 C,2 C,5 C,and 10 C (1 C =200 mA·g-1) for hundreds of cycles,the discharge capacities of the SL-Li2MnO3 reached 218.9,200.5,147.1,and 123.9 mAh·g-1,respectively.The superior performances of the SL-Li2MnO3 are ascribed to the spineMayered integrated structures.With large capacities and superior high-rate performances,these spinel-layered integrate structured materials are good candidates for cathodes of next-generation high-power LIBs.     

生物模板法合成锂离子电池电极材料研究进展

锂离子电池是一类极具潜力的新型二次化学储能器件,被广泛应用于便携式电子设备、电动交通工具和智能电网等领域。高性能电极材料的设计和合成是获得高能量密度、长循环寿命、高安全性锂离子电池的关键。文章针对锂离子电池电极材料存在制备工艺复杂、结构难以控制、活性物质利用率低、循环稳定性和倍率性能差等问题,从生物资源高效利用角度出发,结合生物材料尺寸均匀、形态多变、结构精密、环境友好等优点,综述了生物模板法合成锂离子电池电极材料的研究进展,并对该领域的发展方向进行了展望。