Search

Al impurity is among the most likely components to enter the spent lithium-ion battery (LIB) cathode powder due to the strong adhesion between the cathode material and the Al current collector. However, high-value metal elements tend to be lost during the deep removal of Al impurities to obtain high-purity metal salt products in the conventional hydrometallurgical process. In this work, the harmful Al impurity is designed as a beneficial ingredient to upcycle high-voltage LiCoO2by incorporating robust Al–O covalent bonds into the bulk of the cathode assisted with Ti modification. Benefiting from the strong Al–O and Ti–O bonds in the bulk, the irreversible phase transitions of the upcycled R-LCO-AT have been significantly suppressed at high voltages, as revealed by in situ XRD. Moreover, a Li+-conductive Li2TiO3protective layer is constructed on the surface of R-LCO-AT by pinning slow-diffusion Ti on the grain boundaries, resulting in improved Li+diffusion kinetics and restrained interface side reactions. Consequently, the cycle stability and rate performance of R-LCO-AT were significantly enhanced at a high cutoff voltage of 4.6 V, with a discharge capacity of 189.5 mAhg–1at 1 C and capacity retention of 92.9% over 100 cycles at 4.6 V. This study utilizes the detrimental impurity element to upcycle high-voltage LCO cathodes through an elaborate bulk/surface structural design, offering a strategy for the high-value utilization of spent LIBs.

On the basis of the sustainable concept, organic compounds and carbon materials both mainly composed of light C element have been regarded as powerful candidates for advanced electrochemical energy storage (EES) systems, due to theie merits of low cost, eco-friendliness, renewability, and structural versatility. It is investigated that the carbonyl functionality as the most common constituent part serves a crucial role, which manifests respective different mechanisms in the various aspects of EES systems. Notably, a systematical review about the concept and progress for carbonyl chemistry is beneficial for ensuring in-depth comprehending of carbonyl functionality. Hence, a comprehensive review about carbonyl chemistry has been summarized based on state-of-the-art developments. Moreover, the working principles and fundamental properties of the carbonyl unit have been discussed, which has been generalized in three aspects, including redox activity, the interaction effect, and compensation characteristic. Meanwhile, the pivotal characterization technologies have also been illustrated for purposefully studying the related structure, redox mechanism, and electrochemical performance to profitably understand the carbonyl chemistry. Finally, the current challenges and promising directions are concluded, aiming to afford significant guidance for the optimal utilization of carbonyl moiety and propel practicality in EES systems.

Layered sodium transition-metal (TM) oxides generally suffer from severe capacity decay and poor rate performance during cycling, especially at a high state of charge (SoC). Herein, an insight into failure mechanisms within high-voltage layered cathodes is unveiled, while a two-in-one tactic of charge localization and coherent structures is devised to improve structural integrity and Na+transport kinetics, elucidated by density functional theory calculations. Elevated Jahn–Teller [Mn3+O6] concentration on the particle surface during sodiation, coupled with intense interlayer repulsion and adverse oxygen instability, leads to irreversible damage to the near-surface structure, as demonstrated by X-ray absorption spectroscopy and in situ characterization techniques. It is further validated that the structural skeleton is substantially strengthened through the electronic structure modulation surrounding oxygen. Furthermore, optimized Na+diffusion is effectively attainable via regulating intergrown structures, successfully achieved by the Zn2+inducer. Greatly, good redox reversibility with an initial Coulombic efficiency of 92.6%, impressive rate capability (86.5 mAh g–1with 70.4% retention at 10C), and enhanced cycling stability (71.6% retention after 300 cycles at 5C) are exhibited in the P2/O3 biphasic cathode. It is believed that a profound comprehension of layered oxides will herald fresh perspectives to develop high-voltage cathode materials for sodium-ion batteries.

The expedited synthesis of advanced bifunctional catalysts from waste resources is promising for improving the application of Zn–air batteries (ZAB). In this study, a self-vulcanization strategy was developed to directly transform industrial organic cobalt dimethyldithiocarbamate (CDC) residue into bifunctional oxygen electrocatalysts with an N,S-codoped carbon skeleton and a Co1–xS/Co9S8heterogeneous interface. The catalytic activity of the CDC-derived catalysts depended on the self-vulcanization temperature. CDC-800 exhibited bifunctional catalytic activity for oxygen evolution (η = 371 mV at 10 mA cm–2) and oxygen reduction (E1/2= 0.76 V) reactions. The assembled rechargeable ZAB with a CDC-800 air cathode exhibited an excellent peak power density (75.2 mW cm–2), specific capacity (873 mA h gZn–1), and cycle stability (over 670 h), respectively. This superior catalytic performance mainly resulted from the self-vulcanized Co1–xS/Co9S8heterogeneous interface. Therefore, direct self-vulcanization of organic cobalt residues can contribute to the reduction of the pollution caused by hazardous wastes and sustainable preparation of high-performance bifunctional catalysts.

Lithium metal batteries (LMBs) offer significant advantages in energy density and output voltage, but they are severely limited by uncontrollable Li dendrite formation resulting from uneven Li+behaviors and high reactivity with potential co-solvent plating. Herein, to uniformly enhance the Li behaviors in desolvation and diffusion, the local Li+solvation shell structure is optimized by constructing an anion-braking separator, hence dynamically reducing the self-amplifying behavior of dendrites. As a prototypal, two-dimensional lithiated-montmorillonite (LiMMT) is blade-coated on the commercial separator, where abundant −OH groups as Lewis acidic sites and electron acceptors could selectively adsorb corresponding FSI–anions, regulating the solvation shell structure and restricting their migration. Meanwhile, the weakened anion mobility delays the time of breaking electrical neutrality, and the Li nucleation density is quantified through the respective experimental, theoretical and spectroscopical results, providing a comprehensive understanding of modifying anion and cation behaviors on dendritic growth suppression. As anticipated, a long Li plating/stripping lifespan up to 1800 h and a significantly increased average Coulombic efficiency of 98.8% are achieved under 3.0 mAh cm–2. The fabricated high-loading Li-LFP or Li-NCM523 full-cells display the cycle durability with enhanced capacity retention of nearly 100%, providing the instructive guide towards realizing dendrite-free LMBs.

Cathodes with high cycling stability and rate capability are required for ambient temperature sodium ion batteries in renewable energy storage application. Na3V2(PO4)3is an attractive cathode material with excellent electrochemical stability and fast ion diffusion coefficient within the 3D NASICON structure. Nevertheless, the practical application of Na3V2(PO4)3is seriously hindered by its intrinsically poor electronic conductivity. Herein, solvent evaporation method is presented to obtain the nitrogen-doped carbon coated Na3V2(PO4)3cathode material, delivering enhanced electrochemical performances. N-Doped carbon layer coating serves as a highly conducting pathway, and creates numerous extrinsic defects and active sites, which can facilitate the storage and diffusion of Na+. Moreover, the N-doped carbon layer can provide a stable framework to accommodate the agglomeration of the electrode upon electrode cycling. N-Doped carbon coated Na3V2(PO4)3(NC-NVP) exhibits excellent long cycling life and superior rate performances than bare Na3V2(PO4)3without carbon coating. NC-NVP delivers a stable capacity of 95.9 mA·h/g after 500 cycles at 1 C rate, which corresponds to high capacity retention(94.6%) with respect to the initial capacity(101.4 mA·h/g). Over 91.3% of the initial capacity is retained after 500 cycles at 5 C, and the capacity can reach 85 mA·h/g at 30 C rate.

The 3-D visual positioning of aviation engine rotor bolts is of great significance for automatic connection status detection. However, the internal aviation engine rotor space is narrow, and the shooting angle is limited. Existing vision-based positioning methods based on vertical shooting are insufficient to meet aviation bolt positioning requirements. In this article, a robust bolt visual positioning method at arbitrary shooting angles is proposed. First, a deep learning-based object detection method is employed to extract bolts from both the color image and depth image. Then, an arc-support line segments (ASLSs) method based on generative adversarial network (GAN) preprocessing (ASLS-G) is used to detect multiple elliptical targets from the low-pixel color region of the bolt (CROB). By fusing color image and depth image information, an adaptive threshold slice vector (ATSV) algorithm is proposed to screen out the elliptical targets corresponding to the bottom of the bolts. Finally, a symmetrical depth mean (SDM) algorithm is proposed to obtain the depth value of the bolts and calculate their 3-D coordinates. The experimental results show that the mean absolute error of the bolt coordinate values in each direction in the bolt coordinate system is less than 0.8968 mm, and the standard deviation does not exceed 0.1636 mm, which verifies the effectiveness of the proposed method. Measurement experiments were conducted on the distance between bolts and the bolt distribution radius for a real aviation engine rotor, demonstrating that the proposed method can be applied to a broader range of real-world scenarios.

The diversification of metal elements with similar physicochemical characteristics in lithium-ion batteries (LIBs) results in great challenges in the recycling of spent LIBs. Aiming at eco-friendly, efficient, and industrial-applicable recycling, we propose a novel carbothermic reduction strategy for selective extraction of lithium and sustainable recovery of high-value metals from spent LiNixCoyMn1–x–yO2(NCM) cathode. The reduction mechanism and phase structure evolution of spent NCM revealed that the spent NCM microspheres are converted into multicomponent particles of water-soluble lithium salts (Li2CO3and Li2O) and water-insoluble M or MO (M = Ni, Co, Mn) after carbothermic reduction. Depending on the different properties of the reduced products, two different recycling routes were proposed based on disparate roasting temperatures. In the low-temperature route, 96.6% of Li can be selectively leached out by using water as the only leaching reagent after roasting at 550 °C for 1 h. For the high-temperature route, 98.1% of Li is selectively extracted by water leaching; after that, wet-magnetic separation was employed to collect transition metals depending on the magnetic differences of the product. In particular, the whole process is simple and eco-friendly and has no other chemical consumption. This work provides two efficient and environmentally friendly ways of recycling spent LIBs based on selective lithium extraction.

Sodium layered oxides always suffer from sluggish kinetics and deleterious phase transformations at deep-desodiation state (i.e., >4.0 V) in O3 structure, incurring inferior rate capability and grievous capacity degradation. To tackle these handicaps, here, a configurational entropy tuning protocol through manipulating the stoichiometric ratios of inactive cations is proposed to elaborately design Na-deficient, O3-type NaxTmO2cathodes. It is found that the electrons surrounding the oxygen of the TmO6octahedron are rearranged by the introduction of MnO6and TiO6octahedra in Na-deficient O3-type Na0.83Li0.1Ni0.25Co0.2Mn0.15Ti0.15Sn0.15O2−δ(MTS15) with expanded O–Na–O slab spacing, giving enhanced Na+diffusion kinetics and structural stability, as disclosed by theoretical calculations and electrochemical measurements. Concomitantly, the entropy effect contributes to the improved reversibility of Co redox and phase-transition behaviors between O3 and P3, as clearly revealed by ex situsynchrotron X-ray absorption spectra and in situX-ray diffraction. Notably, the prepared entropy-tuned MTS15 cathode exhibits impressive rate capability (76.7% capacity retention at 10 C), cycling stability (87.2% capacity retention after 200 cycles) with a reversible capacity of 109.4 mAh g–1, good full-cell performance (84.3% capacity retention after 100 cycles), and exceptional air stability. This work provides an idea for how to design high-entropy sodium layered oxides for high-power density storage systems.

Na4Fe3(PO4)2(P2O7) (NFPP) is an attractive candidate for Na+batteries (SIBs) and Li+batteries (LIBs). However, the real implementation of NFPP has been critically restrained by the inferior intrinsic electronic conductivity. Herein, in situcarbon-coated mesoporous NFPP, obtained via freeze drying and heat treatment, demonstrates highly reversible insertion/extraction of Na+/Li+. Mechanically, the electronic transmission and structural stabilities of NFPP are significantly enhanced by the graphitized carbon coating layer. Chemically, the porous nanosized structure shortens Na+/Li+diffusion paths and increases the contact area between the electrolyte and NFPP, ultimately rendering fast ion diffusion. Greatly, long-lasting cyclability (88.5% capacity retention for over 5000 cycles), decent thermal stability at 60 °C, and impressive electrochemical performances are demonstrated in LIBs. The insertion/extraction mechanisms of NFPP in both SIBs and LIBs are systematically investigated, confirming its small volume expansion and high reversibility. The superior electrochemical performances and the insertion/extraction mechanism investigation confirm the feasibility of utilizing NFPP as a cathode material for Na+/Li+batteries.

Lithium metal, the most promising anode material, is receiving increasing interest owing to its high theoretical capacity (3860 mA h g–1) and low negative potential (−3.04 V vs. standard hydrogen electrode). However, the uneven Li dissolution/deposition behavior causes a degraded cycle stability and safety issues, thus seriously restricting the application of Li-metal batteries (LMBs). Separator modification is one of the most versatile and feasible approaches to overcome this problem. In this study, polypropylene (PP) separators are prepared and coated with an inert hexagonal boron nitride (h-BN) layer, which can provide sufficient ion transport channels and physical protection. The h-BN@PP separator exhibits a remarkable effect on the regulation of the diffusion and nucleation of Li+to realize a homogeneous Li microstructure, thereby reducing the voltage polarization and improving the cycle performance of the battery. All LMBs equipped with the modified separators exhibit excellent cycling stabilities. The Li|Li symmetric cell exhibits a stable cycling for over 2300 h with a polarization voltage of 13 mV. In conclusion, the modified h-BN@PP separator has significant potential for stabilizing various Li metal anodes, which strongly promotes the applications of advanced LMBs.

Given the inherent features of open tunnel-like structures, moderate lithiation potential (1.0–3.0 V vs Li/Li+), and reversible redox couples (Nb5+/Nb4+and Nb4+/Nb3+redox couples), niobium-based oxides with Wadsley–Roth crystallographic shear structure are promising anode materials. However, their practical rate capability and cycling stability are still hindered by low intrinsic electronic conductivity and structural stability. Herein, ultrathin carbon-confined Nb12O29materials with rich oxygen vacancies (Nb12O29–x@C) were designed and synthesized to address above-mentioned challenges. Computational simulations combined with experiments reveal that the oxygen vacancies can regulate the electronic structure to increase intrinsic electronic conductivity and reduce the Li+diffusion barrier. Meanwhile, the carbon coating can enhance structural stability and further improve the electronic conductivity of the Nb12O29material. As a result, the as-prepared Nb12O29–x@C exhibits high reversible capacity (226 mAh g–1at 0.1 A g–1), excellent high-rate performance (83 mAh g–1at 5.0 A g–1), and durable cycling life (98.1% capacity retention at 1.0 A g–1after 3000 cycles). The lithium storage mechanism and structural stability of Nb12O29–x@C were also revealed by in situX-ray diffraction (XRD), ex situX-ray photoelectron spectroscopy (XPS), and ex situRaman spectroscopy. When applied as the anode of lithium-ion capacitors (LICs), the as-built LIC achieves high energy density (72.4 Wh kg–1) within the voltage window of 0.01–3.5 V, demonstrating the practical application potential of the Nb12O29–x@C materials.

P2-Na0.66MnO2cathode shows large capacities, but it suffers from rapid capacity fade due to the instability of the interlayer structure. Cu-substitution can effectively suppress the expansion/contraction of MnO6octahedron, thus acting as a buffer.

Fast zinc ion diffusion alloy layer delivers fast 3D diffusion and uniform distribution of zinc ions across the lateral plane to realize the highly reversible Zn plating/stripping process.

The Eu-LMO cathode structural stability and performance are significantly enhanced, attributed to the effective suppression of Jahn-Teller distortion.

Solid polymer electrolyte (SPE) has been considered as promising candidate electrolyte for solid-state lithium metal battery. However, the low ion conductivity and poor interface stability seriously hinder the development of SPE. Introducing the functional filler is a commonly used and effective approach to solving these issues. The poor compatibility and ambiguous mechanism of action are currently the main challenges. In this study, we design and synthesize carbon dots (NSFCDs) with quaternary functional groups, which are introduced into the SPE in the polymerization process of hybrid polymer electrolyte (HPE). The detailed effect law of polyfunctional groups on the polymer chain structure, interface structure of electrolyte/electrode and ion migration is systematically revealed. The dense polymer network endows HPE with enhanced mechanical properties. Through the regulation of polymer segments, the coordination environment of lithium ions is altered, promoting ion transport. The solid electrolyte interface (SEI) induced by NSFCDs and lithium salt anions effectively improves the morphology of lithium ion deposition and alleviates volume strain. As a result, the HPE based on polyethylene oxide (PEO) constructed by free radical polymerization of NSFCDs and polyethylene glycol diacrylate (PEGDA) exhibits excellent comprehensive performance, the assembled Li symmetric battery can cycle stably for 4000 h.

As a new type cathode material for aqueous zinc-ion batteries (ZIBs), manganese-based sulfides have gradually received researchers’ concern in recent years due to their lower electronegativity, higher electronic conductivity and better electrochemical activity compared with the corresponding manganese-based oxides. However, the revelation of energy storage mechanism for manganese-based sulfides is full of great challenges, which largely restricts their application. Herein, inspired by density functional theory calculations, we design and synthesize the γ-MnS and α-MnS hollow microspheres with different crystallographic types for the first time, delivering significantly different energy storage mechanisms of the two MnS electrodes. Impressively, the γ-MnS electrode can stably exist and store energy during the whole charging/discharging processes, while the α-MnS electrode first undergoes irreversible in situ oxidation to generate ZnMnO3/MnOxduring the initial charging process, and then the reversible H+/Zn2+co-insertion/extraction energy storage behavior occurs during the subsequent discharging/charging processes. This unique phase transition mechanism caused by in situ electrochemical oxidation enables the α-MnS electrode to achieve enhanced ion diffusion kinetics, thereby improving the rate capability and cyclic stability. This work not only enriches the energy storage mechanism of manganese-based sulfide cathodes, but also offers research ideas for the design and development of advanced manganese-based cathodes.

Ion electrokinetic regulation in electrolyte is of great significance to alleviating polysulfide shuttling and dendritic growth in lithium-sulfur (Li-S) batteries. Inspired by the tunable solute-polymer interactions of ion exchange membrane, herein we implant an ion-selective “skin” constructed by isocyanoethyl methacrylate grafted polyethylenimine (PEI-IEM) in electrolyte via in situgelation. This tailored skin endows the PEI-IEM-based gel polymer electrolyte (GPE) with a hyper-branched network with abundant polar groups, thus upgrading the electrolyte flame resistance, realizing obstruction on polysulfide migration, and facilitating Li+transport against uneven deposition. Consequently, the PEI-IEM-based GPE empowers enhanced S electrochemical reversibility and high security, as evidenced by a 10 Ah Li-S pouch cell with a low electrolyte/S ratio of 2.6 and 1.4× excess Li anode that delivers an energy density of 412.7 Wh kg−1. This proof-of-concept study provides new insights for tailoring the ionic behaviors of electrolyte to achieve high-energy and safe Li-S batteries.

Aqueous Zn metal batteries suffer from rapid cycling deterioration due to the severe water corrosion and dendrite growth on Zn anodes. Herein, a highly antiwater Znx-diethylenetriaminepenta(methylene-phosphonic acid) interface layer with good zinc affinity and special nanoscaled 3D granular structure is designed on Zn metal to address these problems. Experimental results combined with theoretical analysis and COMSOL simulations reveal that the hydrophobic groups in such Zn-based organic complex are the decisive factor in preventing H2O from damaging Zn anode surface. The massive Zn2+attractive sites formed by interaction of methylene-phosphonic acid groups and Zn cause ion channel for fast zinc-ion adsorption and migration. And the developed nano granular architecture on the surface induces redistributed Zn2+ion flux to realize homogenization with smooth and compact surface deposition. Under the synergism, such modified anodes exhibit long cycling lifespan over 1300 h with a relatively low polarization voltage at 5 mA cm–2. Also, the assembled full cells (including Zn//V2O5and Zn//MnO2cell) based on this anode are also demonstrated. The work provides a simple, low cost, and efficient pathway by combining the two concepts of structural design and constructing protective layers on the surface to prepare high-performance Zn anodes toward prospering aqueous zinc–metal batteries.

This review summarizes the up-to-date developments of composite electrolyte from three approaches: ion transport path, ionic conductivity, interfacial issues.