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Lithium-ion batteries (LIBs) are greatly limited in their practical application because of their poor cycle performance, low conductivity and volume expansion. Herein, molten salts (MSs) FeCl3·6H2O-NMP with low temperature via simple preparation are used as the anode material of LIBs for the first time to break through the bottleneck of LIBs. The good fluidity and high self-healing of FeCl3·6H2O-NMP effectively avoid the collapse and breakage of the structure. Based on this feature, the initial discharge specific capacity reached 770.28 mA h g-1, which was more than twice that of the commercial graphite anode. After 200 cycles at a current density of 100 mA g-1, the specific capacity did not decrease rather it was found to be higher than the initial discharge specific capacity, reaching 867.24 mA h g-1. Besides, the good conductivity of MSs provides convenience for the removal and intercalation of Li+. The active H sites that can combine with lithium ions form LiH and provide capacity for LIBs. Density functional theory (DFT) calculation also provided theoretical proof for the mechanism of LIBs. [ABSTRACT FROM AUTHOR]

Solid-state electrolytes (SSEs) are the key materials in the new generation of all-solid-state lithium ion/metal batteries. Metal–organic frameworks (MOFs) are ideal materials for developing solid electrolytes because of their structural diversity and porous properties. However, there are several significant issues and obstacles involved, such as lower ion conductivity, a smaller ion transport number, a narrower electrochemical stability window and poor interface contact. In this review, a comprehensive analysis and summary of the unique ion-conducting behavior of MOF-based electrolytes in rechargeable batteries are presented, and the different design principles of MOF-based SSEs are classified and emphasized. Accordingly, four design principles for achieving these MOF-based SSEs are presented and the influence of SSEs combined with MOFs on the electrochemical performance of the batteries is described. Finally, the challenges in the application of MOF materials in lithium ion/metal batteries are explored, and directions for future research on MOF-based electrolytes are proposed. This review will deepen the understanding of MOF-based electrolytes and promote the development of high-performance solid-state lithium ion/metal batteries. This review not only provides theoretical guidance for research on new MOF-based SSE systems, but also contributes to further development of MOFs applied to rechargeable batteries. [ABSTRACT FROM AUTHOR]

Cellulose nanocrystals (CNCs) are bioderived one-dimensional species with versatile surface chemistry and unique self-assembling behavior in aqueous solutions. This work presents a scientific approach to leverage these characteristics for creating CNC network templates and processing them to engineer a novel silicon (Si)-based material called silicon nano-quill (SiNQ) for energy storage applications. The SiNQ structure possesses a porous, tubular morphology with a substantial ability to store lithium ions while maintaining its structural integrity. The presence of Si suboxides in the SiNQ structure is demonstrated to be crucial for realizing a stable cycling performance. One of the defining attributes of SiNQ is its water dispersibility due to Si–H surface bonds, promoting water-based Si-graphite electrode manufacturing with environmental and economic benefits. The incorporation of only 17 wt% SiNQ enhances the capacity of graphitic anodes by ∼2.5 times. An initial coulombic efficiency of 97.5% is achieved by employing a versatile pre-lithiation. The SiNQ-graphite anodes with high active loading, when subjected to accelerated charging/discharging conditions at 5.4 mA cm−2, exhibit stable cycling stability up to 500 cycles and average coulombic efficiency of >99%. A generalized physics-based cyclic voltammetry model is presented to explain the remarkable behavior of SiNQs under fast-charging conditions. [ABSTRACT FROM AUTHOR]

High abundance 6Li and 7Li are essential materials for the nuclear industry. In this article, the lithium isotope separation effect and lithium-ion transport of a "lithium salt aqueous solution (anolyte)‖crown ethers–ionic liquid organic solution‖ammonium chloride aqueous solution (catholyte)" electromigration system with B12C4, B15C5 and B18C6 as phase transfer catalysts were investigated systematically. The results show that separation factors can reach 1.028 (B12C4), 1.024 (B15C5) and 1.011 (B18C6), respectively, when LiCl solution is used as the anolyte. The separation effect mainly originated from interfaces between anolytes and organic solutions, and was less affected by an electric field. The separation effect between organic solution and catholytes was greatly affected by the electric field for B12C4 and B15C5 systems, which converted from 7Li-enrichment to 6Li-enrichment with increased voltage. For the B18C6 system it was less affected. Furthermore, lithium ion transport in B12C4, B15C5 and B18C6 systems was greatly promoted by the electric field, with the Li+ concentration in catholytes of B12C4, B15C5 and B18C6 systems increased from 0.088 mg L−1, 0.286 mg L−1 and 0.778 mg L−1 to 8.321 mg L−1, 7.422 mg L−1 and 4.631 mg L−1 respectively as the voltage increased from 2 V to 16 V. The B12C4 system has been confirmed as the optimal solution considering both the Li+ transport and isotope separation effect. [ABSTRACT FROM AUTHOR]

Lithium isotopes with high abundances (6Li and 7Li) are crucial for the advancement of nuclear energy. In order to achieve the effective separation of 7Li, a Sudan I-[HMIm][BF4]-anisole extraction system was built employing Sudan I (1-benzeneazo-2-naphthol) as the extractant and hydrophobic ionic liquid [HMIm][BF4] as the co-extractant. By optimizing the organic and aqueous phase components, the extraction rate of the system could reach up to 26.30%, and the single-stage separation factor of the system could reach 1.015 ± 0.001. Meanwhile, the mechanism of the extraction process was investigated, and it was found that the ratio of Sudan I to lithium ions is 1 : 1, and the thermodynamic enthalpy change of the extraction process was less than zero (ΔH < 0), indicating that the extraction process of the system was an exothermic process. The construction of the Sudan-ionic liquid extraction separation system provides a new idea for the study of 7Li enrichment and separation and also provides a possibility for the industrialization of high-abundance 7Li enrichment. [ABSTRACT FROM AUTHOR]

Owing to their unique molecular structure and chemical reactivity, Keggin-Al13 ([AlO4Al12(OH)24(H2O)12]7+) ions demonstrate versatility in various chemical reactions. Herein, ruthenium oxide nanosheets are introduced as a promising host material for the intercalation of Keggin-Al13 ions with the aim to enhance electrochemical energy storage. Ruthenium oxide, known for its high energy density as an anode material in lithium-ion batteries, faces limitations in terms of cycling stability caused by volume expansion during lithiation. To address these limitations, an approach involving the intercalation of Keggin-Al13 ions into ruthenium oxide nanosheets is developed. The resulting Al13-treated RuO2 (AR-150), heated at 150 °C, maintained the increased interlayer spacing, compared to that of the pristine layered ruthenium oxide. The AR-150 consisting of restacked nanosheets exhibits a considerably increased pseudocapacitance contribution (83.8% at 0.8 mV s−1). In addition, the expanded lamellar structure of AR-150 effectively mitigates volume expansion during repeated lithiation, demonstrating impressive cycling stability. It maintains a reversible capacity of 379.0 mA h g−1 with a capacity retention of 75.0% after 120 cycles at 100 mA g−1. This strategy based on the intercalation chemistry utilizes the unique properties of ruthenium oxide nanosheets to advance their applications in electrochemical energy storage. [ABSTRACT FROM AUTHOR]

Lithium cobalt oxide (LiCoO2) is one of the most commercially successful cathode materials and has attracted much attention from researchers since its discovery. However, an increase in cut-off voltage generates problems such as structural damage and detrimental side reactions. Under this premise, a layer of LiTaO3 coating is sputtered on the surface of the LiCoO2 electrode by magnetron sputtering, which aims to inhibit the structural damage and the occurrence of side reactions under high voltage. Meanwhile, the ionic conductor layer of LiTaO3 can also promote the transmission process of Li+ and improve the power density. The results show that the capacity retention rate of the MS-2 h (magnetron sputtering for 2 hours) electrode is 86.6% at 0.5C for 100 cycles in a voltage range of 3.0–4.6 V, and the capacity of 91 mA h g−1 is achieved at 3C. The cycling stability of the electrode is also effectively improved at high temperature, and the capacity retention rate was 40.9% after 100 cycles at 50 °C. This work proves that the coating of LiTaO3 on the electrode surface by magnetron sputtering can effectively inhibit the damage of the electrode structure and the occurrence of side reactions during cycling and can promote the transmission of lithium ions. [ABSTRACT FROM AUTHOR]

In this investigation, a lithium-free cathode material, Na0.7MnO2.05–Na0.91MnO2, was synthesized by the solid phase method. The intercalation mechanism and partial phase transformation mechanism of NMO600 were clarified by in situ X-ray diffraction and impedance. The design of the heterostructure is favourable for improving the lithium ion storage of NMO600, which can deliver a discharge capacity of 83.12 mA h g−1 at 1 A g−1 and keep 61.71 mA h g−1 after 700 cycles. [ABSTRACT FROM AUTHOR]

The development of anode materials with high theoretical capacity and cycling stability is very important for the electrochemical performance of lithium-ion batteries (LIBs) and sodium-ion batteries (SIBs). Herein, SnSe/NC hollow nanospheres with different crystal orientations were prepared by regulating the high-temperature selenization of the PDA@SnO2 precursor for lithium/sodium storage. In SnSe/NC hollow nanospheres, the physical buffering and chemical bonding of the nitrogen carbon matrix and SnSe nanoparticles could inhibit volume expansion and polyselenide loss, thus maintaining long-term structural stability. More importantly, electrochemical tests and DFT calculations show that the diffusion energy barrier of Li+/Na+ is significantly reduced at the SnSe (400) rather than the usual (111) facet, which is conducive to the uniformity of ion insertion into SnSe, thus effectively enhancing the reaction kinetics and reversibility of lithium/sodium storage. Therefore, SnSe/NC hollow nanospheres with rich SnSe (400) and good dispersion formed at 550 °C delivered the best reversible specific capacity and rate performance. After a long period of 900 cycles, the capacity retention of lithium/sodium ion batteries is close to 84.88% and 77.05%, respectively. Our findings provide valuable insights into the design of metal selenides for advanced LIBs/SIBs. [ABSTRACT FROM AUTHOR]

Accurate Li isotope analysis of silicate glasses using secondary ion mass spectrometry (SIMS) is challenging due to the matrix effect, which causes instrumental mass fractionation (IMF). The characteristics of the matrix effect vary for each element, necessitating empirical correction methods. Here, we present Li isotopic measurements on a set of silicate glasses spanning a broad compositional range from ultramafic to highly siliceous using a Cameca NanoSIMS 50L. A radio-frequency (RF)-O primary beam with an intensity of 1 nA was rastered over a 5 × 5 μm2 area on the sample, and the secondary ions 6Li, 7Li and 30Si were simultaneously detected. We observed a significant matrix effect on δ7Li in the silicate glasses, which yielded an IMF of up to 19‰, exceeding the analytical precision of <2.5‰ (1SD). The IMF is strongly correlated with the chemical compositions of the silicate glasses. To correct the matrix effect, we employed various correction schemes, including univariate and multivariable compositions. All results consistently indicated that silica exerted a dominant influence on the IMF. We then propose a straightforward "online" method to correct this silica-related matrix effect by utilizing simultaneously measured 30Si signals. This strategy improves the accuracy of the Li isotope measurements to within 3‰ and can be widely applied to anhydrous subalkaline magmatic glasses with compositions ranging from ultramafic to highly siliceous. [ABSTRACT FROM AUTHOR]

The binary composite, ZnSnO3 microcubes (ZSO MC) homogeneously parceled in an N-doped carbon nanofiber membrane (ZSO@CNFM), was synthesized via a mild hydrothermal, electrospinning and carbonization process as a flexible lithium-ion battery (LIB) anode material. The unique carbon-coating layer architecture of ZSO@CNFM not only plays a crucial role in alleviating the volume change of ZSO MC during lithium ion insertion/extraction processes, but also constructs a three-dimensional (3D) transport network with the help of interconnected carbon nanofibers (CNFs) to ensure the structural integrity of the material and promote the electrochemical reaction kinetics. Due to its good flexibility characteristics, the as-prepared ZSO@CNFM can be directly adopted as an anode material for LIBs without the use of copper foil, conductive carbon black and any binder. Electrochemical surveying results manifest that the optimal ZSO@CNFM electrode displays excellent cycling stability (582.6 mA h g−1 after 100 lithiation/delithiation cycles at 100 mA g−1), high coulombic efficiency (CE, 99.6% at 100th cycles), and superior rate performance (349.5 mA h g−1 at 2 A g−1). The good electrochemical properties can be ascribed to the synergistic effect of the high theoretical specific capacity of ZSO MC, favourable stability of the carbon substrate, the open structure of ZSO@CNFM and the 3D continuous highly conductive framework for rapid electron/ion transfer. [ABSTRACT FROM AUTHOR]

The spinel LiMn2O4 cathode has received substantial attention from researchers owing to its high voltage plateau, eco-friendliness, and cost-effectiveness. Nevertheless, its practical application has been impeded by severe capacity attenuation due to the Jahn–Teller effect and spontaneous disproportionation reaction. To overcome these issues, this study synthesized a series of manganese-based metal–organic frameworks with varying structures using aromatic carboxylic acids that contain different numbers of carboxyl groups as organic frameworks. These frameworks were then used as precursors for synthesizing spinel LiMn2O4 cathode materials. This approach aims to enhance capacity, cycle stability, and rate performance by reducing the diffusion resistance of lithium ions, exposing the (111) plane, and increasing the Mn3+ content. The LMO-PMA sample exhibited remarkable cycling stability (91.4% after 1000 cycles at 10C) and superior capacity (140.2 mA h g−1 at 0.2C, 113.1 mA h g−1 at 10C). This approach can be extended to the synthesis of other cathode materials. [ABSTRACT FROM AUTHOR]

We report the improved kinetic mechanism of a nickel-rich LiNi0.84Mn0.10Co0.03Al0.03O2 cathode. The important role of Co/Al in inhibiting cation disorder to increase the lithium ion diffusion rate is revealed. Impressively, it retains an excellent capacity retention of 76.8% after 200 cycles under the high-rate condition (5C). [ABSTRACT FROM AUTHOR]

Due to its remarkably high specific capacity of 3860 mA h g−1 and low reduction potential (−3.04 V vs. SHE), lithium metal has been identified as an ideal anode candidate for high-energy density lithium-ion cells. However, the growth of lithium dendrites caused by the deposition of lithium metal can affect the charge and discharge behavior of a cell and lead to short circuit, which is a safety concern and hinders its practical applications. Here, we prepare a composite separator polypropylene-Li1+xAlxTi2−x(PO4)3-indium tin oxide (PP–LATP–ITO) via a simple slurry coating method. The coating of LATP-ITO demonstrates unique advantages of Li-ion deposition as well as interfacial chemistry. Firstly, lithiophilic PP-ITO helps to reduce the energy barrier for Li deposition. In addition, the three-dimensional ion channels can regulate the transport of lithium ions and induce uniform Li metal plating and stripping. Furthermore, the in situ formed interface comprising of a Li–In alloy, Li3PO4 and LiF enables stable interfacial chemistry. As a result, compared with the PP separators, the voltage stability of the composite separators in Li–Li symmetric cells is greatly improved during the charge and discharge cycling. In addition, LCO/Li cells with the composite separator PP–LATP–ITO exhibit a higher specific capacity (140 mA h g−1) and good capacity maintenance during cycling. This work proposes a separator coating strategy that can inhibit dendrite formation and stabilize the lithium metal interface. [ABSTRACT FROM AUTHOR]

C–C bond formation based on palladium-catalysed cross-coupling reactions using organolithium reagents has seen major breakthroughs in the past decade. However, the use of inert conditions, as well as slow addition of the organolithium species, is generally required. Here we describe the Pd-catalysed cross-coupling of C36H74-gelated organolithium reagents with aryl bromides. The reaction proceeds in 5 min at room temperature, while eliminating the previously required slow addition, and strict use of inert atmosphere. Crucially, the use of organolithium gels facilitates handling, and offers a tremendously increased process safety, which is illustrated by a gram-scale transformation that does not require any extraordinary safety precautions. [ABSTRACT FROM AUTHOR]

Molybdenum disulfide (MoS2) is a very useful catalytic material for energy storage. However, the design and synthesis of special morphologies is required to overcome the poor cycle stability of such materials. We synthesized MoS2 composites embedded with silica using a chemical vapor deposition (CVD) technique and silica nanotemplates and obtained a honeycomb MoS2 nanomaterial with a stable structure and extremely thin single walls. Results of methods including SEM and XRD revealed that honeycomb MoS2 formed a three-dimensional hollow structure in the bulk phase. With this structure, more spatial positions are exposed during lithium-ion storage, meaning it can accommodate higher energy and facilitate the transmission of lithium ions. The honeycomb MoS2 developed in this study was demonstrated to have a high capacity and structural stability. The reversible capacity was as high as 680 mA h g−1 after 100 cycles, which is still higher than the theoretical capacity of MoS2 (670 mA h g−1), with the coulombic efficiency exceeding 99%. Furthermore, the capacity remained at ∼600 mA h g−1 at the 2C rate, demonstrating a superior rate capability. Our study will provide a contribution for studies including the synthesis of MoS2 with special morphology and the optimization of nanomaterials for energy storage. [ABSTRACT FROM AUTHOR]

TiO2 is a promising and safe anode material for lithium-ion batteries. Nevertheless, its inferior electronic conductivity and inferior cycling capability have always limited its practical application. In this study, flower-like TiO2 and TiO2@C composites are produced by a simple one-pot solvothermal method. It is noticeable that the synthesis of TiO2 is carried out simultaneously with carbon coating. The flower-like TiO2 with a special morphology can decrease the distance of lithium ion diffusion, while the carbon coating improves the electronic conductivity of TiO2. At the same time, the carbon content of TiO2@C composites can be controlled by adjusting the amount of glucose. Compared with flower-like TiO2, TiO2@C composites have higher specific capacity and preferable cycling performance. It is noteworthy that the specific surface area of TiO2@C with a carbon content of 63.36% is 293.94 m2 g−1 and its capacity remains at 371.86 mAh g−1 after 1000 cycles at 1 A g−1. Other anode materials can also be prepared using this strategy. [ABSTRACT FROM AUTHOR]

A straightforward carbothermal reduction method was used to synthesize nitrogen-doped carbon-coated LiFePO4 with the carbon and nitrogen sources derived from gelatin. Compared to the bare material, the particles of LiFePO4 composites are smaller, the electrical contact between the grains is improved, and lithium ions diffuse more rapidly in the composites. As a consequence, the structural stability and conductivity are enhanced in LiFePO4 compounds. After 500 cycles, the material delivered 138.2 mA h g−1 at a multiplicity of 1C with 90.2% capacity retention. This result demonstrates that a suitable amount of N-doped carbon layer can enhance the electrochemical performance of LiFePO4. This efficient strategy provides a facile approach to develop excellent performance LiFePO4 materials with promising practical applications. [ABSTRACT FROM AUTHOR]

The conduction mechanism of a family of high concentration lithium electrolytes (HCEs) is investigated. It is found in all HCEs that the molecular motions are regulated by the anion size and correlated to the HCE ionic resistivity. From the results, a mechanism involving highly correlated ionic networks is derived. [ABSTRACT FROM AUTHOR]

Lack of high-performance active materials limits the rapid development of advanced energy storage devices with both high power and high-energy performance. Here, Mn3O4/reduced graphene oxide (RGO) was synthesized as a negative material for both lithium-ion batteries (LIBs) and lithium-ion capacitors (LICs). The RGO prevents the aggregation of Mn3O4 and enhances the charge transport rate, enabling Mn3O4/RGO to exhibit high specific capacity, superior rate performance, and long cycling stability. More significantly, the charge storage of Mn3O4/RGO is mainly from the surface controlled reaction, which accounts for 58.2–83.3% of charge storage capacity when the scan rate increases from 0.1 to 1.0 mV s−1. Owing to high specific capacity and fast reaction kinetics of Mn3O4/RGO, the composite exhibits high energy performance when assembled with a LiNi0.5Co0.2Mn0.3O2 cathode, and achieves both high-energy and high-power performance in LICs after being assembled with activated carbon (AC). The LiNi0.5Co0.2Mn0.3O2//Mn3O4/RGO LIB displays a specific energy of 144.8 W h kg−1 at 215.1 W kg−1, and the AC//Mn3O4/RGO LIC exhibits a specific energy of 98.6 W h kg−1 at 180.1 W kg−1 with a retained specific energy of 70.3 W h kg−1 at a high specific power of 1937.5 W kg−1. [ABSTRACT FROM AUTHOR]

The effect of point defects on the performance of the Li3InCl6 solid electrolyte was investigated using first-principles simulations. The Li-ion conductivity of Li3InCl6 was improved by the presence of point defects, such as a 4g site occupation by In or a Cl vacancy. The diffusion of Li ions was activated by the movement of some Li ions to vacant sites in the In layer, and the point defects reduced the energy barrier of this step, resulting in an overall increase in Li-ion diffusivity. The underlying mechanism of this effect was examined in terms of the structural and chemical properties of Li–Cl and In–Cl bonds, which indicated the energy barrier was closely related to changes in the bond distance and covalent interaction between the migrating Li and nearby Cl ions and nonuniformity among In–Cl bonds. Thermodynamic analysis showed that defect formation was unfavorable during conventional high-temperature synthesis; therefore, it is suggested that heating is applied at low temperatures only as a supplementary process to modify the crystallinity after preparing defective Li3InCl6 crystals by mechanical or solution-based routes to practically implement the effect of point defects and improve the solid electrolyte performance of Li3InCl6. [ABSTRACT FROM AUTHOR]

As a part of our ongoing research, we have synthesized a new fluorescence probe, p-C4A, based on a calix[4]arene substituted with 4-aminoquinoline moieties with amide linkages. p-C4A can selectively recognize Li+ and PO43− ions and has been characterized via an emission study, an absorption study, ESI-MS spectroscopy, a 1H NMR study and cyclic voltammetry. The fluorescence sensor p-C4A can operate over a concentration range of 5–170 nM for Li+ sensing and 5–80 nM for PO43− sensing. The R2 values obtained for the sensing of Li+ and PO43− ions are 0.9962 and 0.9911, respectively. p-C4A demonstrates a minimum detection limit of 6.15 nM for Li+ and 9.0 nM for PO43−. The quantum yields of p-C4A as its Li+ and PO43− ion complexes were found to be 0.014 and 0.27, respectively. Herein, we report an easy-to-use, low-cost, disposable, paper-based, fluorescent, wax-printed device for the rapid chemical screening of Li+ and PO43−. This device can be used as a quick, portable, multiple-test panel that is simple, lightweight, and disposable. Moreover, in order to assess its analytical applicability, the prepared sensor was successfully used for the determination of Li+ and PO43− from wastewater samples, validating the proposed ion recovery method with 96–99% recovery rates. [ABSTRACT FROM AUTHOR]

Rational design and synthesis processes are very important for giving a product an excellent performance. Sn-based anode materials with a high theoretical capacity and suitable working potential usually suffer from severe capacity fading due to their inferior electronic conductivity and obvious volumetric variations, hindering their practical applications. Herein, hierarchical N doped graphene-supported SnO2/Zn2SnO4 (SnO2/Zn2SnO4-NG) is successfully prepared via a facile approach forming a 3D hierarchical configuration. As an anode for lithium-ion batteries, the SnO2/Zn2SnO4-NG anode can reach a high reversible capacity (837 mA h g−1 after 300 cycles at 0.2 A g−1) and rate capability (403 mA h g−1 at 5 A g−1) but also show extraordinary durability. Furthermore, it exhibits an impressive rate performance and maintains superior cycling stability. Such significantly enhanced electrochemical performances of the SnO2/Zn2SnO4-NG anode can be attributed to the unique structural design, which can not only effectively reduce the stress from the discharging/charging process and maintain the structural stability of the electrode during cycling but also alleviate aggregation of the active materials and facilitate electrolyte/ion transport. Meanwhile, Zn2SnO4 can greatly improve the electrical conductivity (confirmed by DFT calculations), and SnO2/Zn2SnO4 can create more active sites for lithium storage. This work thus verifies the great potential of the SnO2/Zn2SnO4-NG composite for applications as a high-performance anode material in next-generation Li storage. [ABSTRACT FROM AUTHOR]

Uncontrollable lithium dendrite growth which typically results in poor cycling stability and safety issues remains a great challenge for lithium metal batteries. Herein, we report a novel separator modification strategy by using polydimethylsiloxane (PDMS) to functionalize a glass fiber separator to inhibit dendrite growth. The PDMS-modified separator not only acts as a mechanical barrier but also promotes the desolvation of lithium ions. Consequently, Li/Li symmetric cells with optimal PDMS-modified separators are able to stably cycle for more than 1200 hours at 2 mA cm−2 with a stable polarization voltage (about 60 mV). Moreover, with the assistance of the functionalized separator, the assembled Li/LiFePO4 full cell can impressively achieve capacity retention up to 82.5% and a coulombic efficiency of ∼99.4% after 200 cycles at 1.0 C. The PDMS functionalization strategy provides a simple and efficient approach for developing safe and high-performance lithium metal batteries. [ABSTRACT FROM AUTHOR]

Molybdenum disulfide (MoS2), with its unique two-dimensional nanostructure and high theoretical capacity, is considered a promising electrode for lithium-ion batteries (LIBs). However, the disadvantages of MoS2 electrodes include low electronic conductivity, sluggish cation kinetics, serious volume change, poor cycle stability, and inefficient rate performance of lithium storage. Herein, oxygen vacancy and heterostructure engineering are rationally involved in revealing the moderate oxygen vacancy in the hierarchical tubular heterostructure material (MoS2@MoO2) via a self-template method as a highly active LIB electrode. Due to the presence of the moderate oxygen vacancies and heterojunction structure of MoS2@MoO2-4, the diffusion pathway and barrier for lithium ions can be significantly reduced, accelerating the ionic diffusion rate and further promoting the reaction kinetics. The electrode achieves a high reversible capacity of 1200.1 mA h g−1 at 100 mA g−1 after 100 cycles with the optimum regulation of the sulfur contents and the moderate oxygen vacancy (MoS2@MoO2-4). Additionally, good rate capability is obtained at stepwise current densities due to the merits of MoS2@MoO2. A series of measurements such as EPR, XPS, in situ XRD, and in situ Raman are also employed to reveal the synergistic effect in the midst of oxygen vacancies and heterostructures for lithium storage. All results prove that the moderate oxygen vacancy and tubular heterostructure can implement faster Li+ transport and lower the diffusion barrier of lithium ions, resulting in enhanced lithium storage performance of MoS2@MoO2. [ABSTRACT FROM AUTHOR]

In this work, magnetically recyclable lithium manganese oxide ion sieves (H1.6(AlxMn1−x)1.6FeyO4, HMO-x–y) with enhanced Li+ adsorption capability were synthesized by Al–Fe co-doping via hydrothermal reactions. XRD characterization showed that the Al–Fe co-doped sample maintained the spinel crystal structure of the undoped HMO-0–0. SEM imaging and EDS mapping indicated that a rough surface with a granular convex morphology was obtained and the doping elements Al and Fe were uniformly dispersed in the grains. Magnetic studies revealed that HMO-0.3–0.1 exhibited a magnetization value of 2.86 emu g−1 and could be separated from solutions effectively using a magnet. Li+ adsorption analysis showed that the equilibrium adsorption capacity of Al–Fe co-doped HMO-0.3–0.1 reached 45.31 mg g−1, which was larger than that of HMO-0.3–0 (33.39 mg g−1) with only Al-doping. In addition, HMO-0.3–0.1 exhibited excellent cycling performance and the Li+ adsorption capacity was maintained over 95% after five cycles. Compared with the Al-doped or Fe-doped sieves, the Al–Fe co-doped lithium ion sieve with excellent adsorption performance and characteristics that can be separated from solutions by a magnetic field is generally regarded as the most promising adsorbent for recovering lithium from salt-lake brines. [ABSTRACT FROM AUTHOR]

The high price of lithium salts hinders the sustainable development of high concentration electrolytes, while the poor electrochemical performance limits the large-scale application of low concentration electrolytes. Herein, the electrochemical performance of a low concentration electrolyte is improved via dual interfacial modification of the fluoroethylene carbonate (FEC) solvent and the lithium difluoro(oxalato)borate (LiODFB) additive. LiODFB is preferentially oxidized via a ring-opening path to generate a lithium fluoride (LiF)-rich inner layer on the surface of a ferrous lithium phosphate cathode, and then a large amount of C–F polycarbonate oligomers is generated in the outer layer via a reaction between LiODFB and FEC. LiF has a large bandgap and a low lithium ion (Li+) diffusion barrier, and the electronegative C–F groups provide the lithiophilic sites to reduce the interaction between Li+ and solvents, resulting in a repulsive force towards the C＝O dipole of the carbonate ester solvent to improve the oxidation stability of the electrolyte. The clever design of the multi-layer cathode electrolyte interphase suppresses the excessive decomposition of the electrolyte, improves the diffusion of Li+, and enables much-improved cycling stability of the cathodes. This work gives a fruitful insight into the key role of cathode electrolyte interphase components in Li+ diffusion and improves the performance of low-concentration electrolytes. [ABSTRACT FROM AUTHOR]

As the economy started to recover from the COVID pandemic, the price of Li2CO3 skyrocketed to its highest. This situation has aggravated concerns about the supply chain for lithium-ion batteries (LIBs). Recycling spent LIBs is a potential solution to alleviate the bottleneck of the supply chain and prevent environmental pollution, and has attracted lots of attention. However, lithium recycling is generally disregarded because of the complex recycling process and its low recycling efficiency. Here, in this work we developed a sustainable lithium recovery process, which can selectively leach and recover lithium with formic acid before recycling valuable metals. With the reported method, lithium can be 99.8% recovered from layered oxide cathode materials with 99.994% purity. In addition, this lithium recovery process is affordable, compared to the typical hydrometallurgical process, by saving 11.15% per kilogram of spent LIBs. Therefore, this research provided a new solution to eliminating the effects of lithium ions on valuable metal separation and the co-precipitation reaction and precluding the influence of other metal ions on lithium recovery. This simplified lithium recovery process provides new opportunities for sustainable recycling of LIBs and economical restoration of the lithium supply chain. [ABSTRACT FROM AUTHOR]

Two-phase heterostructures have received tremendous attention in energy-related fields as high-performance electrode materials. However, heterogeneous interfaces are usually constructed by introducing foreign elements, which disturbs the investigation of the intrinsic effect of the two-phase heterostructure. Herein, unique heterostructures constructed with orthorhombic NiSe2 and cubic NiSe2 phases are developed, which are embedded in in situ formed porous carbon from metal–organic frameworks (MOFs) (O/C-NiSe2@C). Precisely-controlled selenylation of MOFs is crucial for the formation of the O/C-NiSe2 heterostructure. The heterogeneous interfaces with lattice dislocations and charge distribution are conducive to the high-speed transfer of electrons and ions during electrochemical processes, so as to improve the electrochemical reaction kinetics for lithium-ion storage and the hydrogen evolution reaction (HER). When used as the anode of lithium-ion batteries (LIBs), O/C-NiSe2@C shows a superior electrochemical performance to the counterparts with only the cubic phase (C-NiSe2@C), in view of the cycling performance (719.3 mA h g−1 at 0.1 A g−1 for 100 cycles; 456.3 mA h g−1 at 1 A g−1 for 1000 cycles) and rate capabilities (344.8 mA h g−1 at 4 A g−1). Furthermore, O/C-NiSe2@C also exhibits better HER properties than C-NiSe2@C, that is, much lower overpotentials of 154 mV and 205 mV in 0.5 M H2SO4 and 1 M KOH, respectively, at 10 mA cm−2, a smaller Tafel slope as well as stable electrocatalytic activities for 2000 cycles/10 h. Preliminary observations indicate that the unique orthorhombic/cubic two-phase heterostructure could significantly improve the electrochemical performance of NiSe2 without additional modifications such as doping, suggesting the O/C-NiSe2 heterostructure as a promising bifunctional electrode for energy conversion and storage applications. [ABSTRACT FROM AUTHOR]

The extensive application in recent years of lithium-ion batteries (LIBs) based on an LiFePO4 (LFP) cathode in electric vehicles will lead to a large amount of scrapped LFP in the foreseeable future. Therefore, recycling these scrapped cathode materials appropriately will become an extremely important issue. Here, a facile and green method is developed to directly regenerate scrapped LFP into a fresh cathode. We propose a re-lithiation approach that intercalates lithium ions into scrapped LFP in an aqueous solution system. Specifically, the configuration of the recycling device is a H-type electrolytic bath, in which the cathode and anode electrolytes are separated by an anion-exchange membrane, a zinc plate is used as the anode, the scrapped LFP suspension is regarded as the cathode, and the electrolyte is lithium salt aqueous solution. The regenerated LFP is obtained via a discharging process. It is found that the effectiveness of the recycling process is directly related to the parameters of the discharge current (mA) and theoretical intercalation amount of lithium (TIA). The results show that the performance of LFP recycled at a current of 5 mA and 150%-TIA is the best; it has high lithium content and better crystallinity, and it also exhibits excellent electrochemical performance with a high discharge capacity of 134.0 mA h g−1 at 1C and a capacity retention rate of 85.5% after 300 cycles. Furthermore, we adopt FTIR spectroscopy to assess the quality of the regenerated LFP intuitively and simply, thus providing a feasible monitoring standard for industrial production. [ABSTRACT FROM AUTHOR]

A porous V2O5 nanosheet is synthesized via freeze-drying followed by a heat-treatment process. Observably, transmission electron microscopy and atomic force microscopy analysis indicate that a porous and thin layer microstructure is achieved with V2O5. Electrochemical measurement demonstrates that the as-obtained V2O5 exhibits evident advantage toward the sodium/lithium ion storage. When evaluated as a cathode for sodium ion batteries, the V2O5 nanosheet delivers an initial discharge capacity of 199.8 mA h g−1. Even after 200 cycles at 50 mA g−1, the V2O5 nanosheet can retain a capacity of 123.9 mA h g−1, which is 2.3 times higher than that of bulk V2O5. Cyclic voltammetry and electrochemical impedance spectroscopy analysis further confirm that this rationally-designed porous nanosheet can increase the electroactive sites for the redox reaction and shorten the pathway of charge transfer, consequently leading to an enhanced capacitive sodium ion storage behavior. [ABSTRACT FROM AUTHOR]

SiOx is one of the most promising anode materials for lithium-ion batteries (LIBs), due to its high theoretical capacity and low cost. However, the huge volume expansion and low electron/ion diffusion rate hinder its further commercial applications. Herein, a simple molecular polymerization method is developed to synthesize N,P co-doped SiOx–C composites (denoted as SiOx–C@CNT), in which SiOx and carbon are uniformly dispersed at the atomic level, and the embedded carbon nanotubes improve the lithium ion diffusion kinetics. Benefiting from the unique structure, the SiOx–C@CNT composites exhibit a high reversible capacity of 848 mA h g−1 at 0.1 A g−1 and long cycling stability (84.0% capacity retention after 1500 cycles). More impressively, the LiCoO2∥SiOx–C@CNT full battery also exhibits stable cycle life (only 4.7% capacity loss after 300 cycles at 1 C). These results show the application potential of the SiOx–C@CNT anode in LIBs. [ABSTRACT FROM AUTHOR]

The sluggish solid-state diffusion kinetics is the key challenge for turbostratic carbon in lithium-based energy storage. Interconnected mesoporosity and multi-scale structures are effective ways of optimizing the kinetics. Herein, a novel strategy of multi-stage explosion through calcium oxalate (CaC2O4) thermal decomposition was designed to prepare a defect-rich popcorn-like lignin-derived mesoporous carbon cage (PLPCC). The PLPCC prepared by two-stage explosion (PLPCC-700) displays an interconnected mesoporous structure and two-dimensional nanosheets/three-dimensional mesoporous carbon network with abundant active carbonyl and edge nitrogen defects. PLPCC-700 delivers excellent reversible capacity (706.3 mA h g−1 at 0.2 A g−1) and superior rate capability (530.4 mA h g−1 at 1 A g−1). The assembled Li-ion capacitor device delivers a considerable energy density of 79.2 W h kg−1. In this work, a green and delicate strategy is designed to prepare defect-rich carbon from industrial lignin residues for advanced energy storage. [ABSTRACT FROM AUTHOR]

In view of the disadvantage of the limited active site utilization due to the easy aggregation of phthalocyanine compounds, three kinds of graphene composite metal phthalocyanines (TN-MPc@GN, M = Fe, Co, Ni) were prepared using an in situ composite method, and their electrochemical properties were investigated as anode materials for lithium-ion batteries. The layered structure and large specific surface area of graphene are used to disperse phthalocyanine uniformly, so that the conjugated structure (C＝C/C＝N/N＝O) of phthalocyanine is more exposed and the utilization of active sites for embedding lithium ions are greatly enhanced. At the same time, the large surface area is beneficial to the contact between materials and the electrolyte, which results in a faster transmission path. As a result, the first discharge specific capacities of the graphene composite phthalocyanine (TN-MPc@GN, M = Fe, Co, Ni) electrodes are 440.8, 765.0 and 753.9 mA h g−1, respectively. After 420 cycles, the specific capacities increased to 734.6, 844.7 and 949.1 mA h g−1, respectively, which are much higher than those of the pristine three phthalocyanine (TN-MPC, M = Fe, Co, Ni) electrodes without the graphene composite. Using the graphene composite can be an effective strategy to improve the utilization of active sites of organic electrode materials in lithium-ion batteries. [ABSTRACT FROM AUTHOR]

In recent years, the research on iron-based graphene composites in the field of energy storage has been extensive. However, the synthesis of most of these materials requires a lot of energy and the particles tend to agglomerate on the graphene surface. Therefore, the simple and low-cost method to synthesize small-particle iron-based graphene composites is still a scientific research subject worthy of in-depth study. In this paper, we obtain the amorphous Fe2O3 nanoparticle@dry graphene oxide composites (am-Fe2O3-dGO) in a low-cost and straightforward way at room temperature. The obtained amorphous Fe2O3 nanoparticles are uniformly distributed on the dried GO (dGO) film and these tiny nanoparticles loaded on graphene provide excellent conditions for the diffusion of lithium ions. In addition, the amorphous nature of Fe2O3 also helps decorated dGO achieve remarkable cycling stability and rate performance. After low-temperature modification of am-Fe2O3, the lithium-ion storage capacity of dGO increased by about 158%. The specific capacities of dGO and am-Fe2O3-dGO for the first charge are 258 and 667 mA h g-1 at 0.1 A g-1, respectively. This work shows that the lithium storage performance of dGO was significantly improved by the modification of am-Fe2O3. [ABSTRACT FROM AUTHOR]

Solid electrolytes (SEs) are expected to have a wide potential window, excellent stability, and high safety in electrochemical processes, allowing them to be applied flexibly in all-solid-state batteries (ASSBs). However, SEs suffer from low ionic conductivity and high interfacial impedance, which limits their practical application as key components of electrochemically stable batteries. Hf-based metal--organic frameworks modified by lithium ions (HLMOFs), consisting of functionalised UiO-66 MOFs with excellent electrochemical performances, have been synthesised and processed. The Li/UiO-66-2CO2Li (Li/HLMOF-4) electrolyte membrane shows excellent electrochemical performance, including high ionic conductivity (2.82 x 10-3 S cm-1), high transference number (0.58), and a wide potential window of 1.60--4.65 V at room temperature. The lithium stripping/plating behaviours can be stably cycled under a current density from 0.02 to 0.2 mA cm-2. The excellent electrochemical performances of the nanostructured Li/HLMOF-4 are attributed to an increase in protons on the carboxyl group in the crystal by post-synthesis modification, which could be exchanged with lithium ions. The fabricated Li8Li/HLMOF- 48LiFePO4 batteries exhibit high charge/discharge capacities. The chemical and structural design of the Hf-based SEs promotes their practical applications in next-generation solid-state batteries. [ABSTRACT FROM AUTHOR]

Varying the degree of ethylene oxide (EO) functionalization of the zirconium MOF UiO-68 affords two novel MOFs; UiO-68-EO and UiO-68-2EO exhibit solvent-free ionic conductivity upon loading LiTFSI in their pores. Incorporating EO chains provides a pathway for lithium ion migration between the coordinated sites and results in an ionic conductivity of 3.8 × 10−7 S cm−1 and 3.9 × 10−4 S cm−1 at 90 °C for UiO-68-EO/LiTFSI and UiO-68-2EO/LiTFSI respectively. [ABSTRACT FROM AUTHOR]

With a high specific capacity, MoP2 has been identified as an ideal electrode material for LIBs. However, the specific capacity is negatively affected due to its poor conductivity and severe volume expansion during insertion and extraction of Li+. In this paper, MoP2-C synthesized by using a Mo-MOF as a precursor, with the generation of C, can effectively solve the agglomeration problem in the synthesis process and alleviate serious volume changes during cycling. Due to the lack of carbon sources provided by a Mo-MOF, the conductivity of MoP2-C cannot be greatly improved. Therefore, rGO and PPy are added to improve the conductivity of MoP2 and further increase the stability of the structure. Compared with MoP2/C and MoP2/C@PPy, MoP2/C@rGO exhibits the highest initial discharge specific capacity of 1208 mA h g−1 at a current density of 100 mA g−1 and rate performances of 830, 750, 630, 550, and 430 mA h g−1 with the current density increasing from 100 mA g−1 to 2000 mA g−1. Notably, the specific capacity remains at 640 mA h g−1 at a current density of 100 mA g−1 after 100 cycles. Followed by 200 cycles at a current density of 2000 mA h g−1, the specific capacity remains at 395 mA h g−1 with a capacity retention rate of 80%. [ABSTRACT FROM AUTHOR]

A series of N-carbamoyl aziridines has been treated by diethyl phosphite in the presence of n-BuLi to afford α-methylene phosphonate aziridines in modest yields. The study of the reaction's scopes and the analysis of byproducts indicated that this transformation proceeds via a unique mechanism. The mechanism that produces the α-methylene phosphonate relies on the use of BuLi, where both the lithium ion and then the presence of the nucleophilic butyl is essential. In addition, the nature of the final compound, either α-methylene phosphonate or α-methylene-gem-bisphosphonate derivatives containing an aziridine motif, is highly dependent on the nature of the base used. [ABSTRACT FROM AUTHOR]

A three-dimensional (3D) metal–organic framework containing Li-oxygen clusters, namely {[Li2(IPA)]·DMF}n (1) (H2IPA = isophthalic acid), has been constructed under solvothermal conditions. The Li-based MOF can be applied to lithium energy storage. For example, it shows good compatibility with a PEO (LiTFSI) solid-state polymer electrolyte (SSPE). The PEO (LiTFSI) with the MOF additive shows an ionic conductivity of 1.1 × 10−5 S cm−1 at room temperature. The 1D rhombic channels should facilitate lithium ion transportation and provide fast lithium ion pathway. Having assembled the PEO-MOF SSPE in a Li/Li symmetric cell and cycled at a current density of 0.1 mA cm−2, the polarization voltage was below 0.1 V during a 100 h test. The PEO-MOF SSPE was also used in a LiFePO4-Li full cell and a high specific capacity of 144 mA h g−1 was achieved. [ABSTRACT FROM AUTHOR]

Single-phase magnesium molybdate, MgMoO4, is successfully synthesized by a facile sol-gel method. Attributed to the multielectron reaction and the synergistic effect of the elements molybdenum (Mo) and magnesium (Mg), the MgMoO4 electrode exhibits excellent electrochemical properties. After activation, benefiting from the decrease in particle size and the uniform nanosphere morphology, the MgMoO4 electrodes can deliver a stable high specific capacity of about 1060 mA h g−1 at a current density of 100 mA g−1 after 600 cycles. Based on the important role of the activation process, electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM) and scan rate cyclic voltammetry (CV) measurement methods were employed to reveal the effect of the activation process on the electrochemical behavior of the electrode material. Furthermore, by combining the in situ X-ray diffraction (XRD) and ex situ X-ray photoelectron spectroscopy (XPS) results, we illustrate the lithium storage mechanism of the MgMoO4 electrode in detail. [ABSTRACT FROM AUTHOR]

The electron and ion conductivities of anode materials such as MnOx affect critically the properties of anodes in Li-ion batteries. Herein, a three-dimensional (3D) nanofiber network (MnOx-MXene/CNFs) for high-speed electron and ion transport with a MnOx surface anchored and embedded inside is designed via electrospinning manganese ion-modified MXene nanosheets and subsequent carbonization. Ion transport analysis reveals improved Li+ transport on the MnOx-MXene/CNF electrode and first-principles density functional theory (DFT) calculation elucidates the Li+ adsorption and storage mechanism. The surface-anchored MnOx nanoparticles form extremely strong bonds with the nanofibers, and the internally embedded MnOx nanoparticles, due to the fiber confinement effect, ensure the structural stability during charging and discharging, achieving the so-called dual stabilization strategies for cyclic fluctuation. By electrospinning, self-restacking of MXene flakes can be prevented, thereby giving rise to a larger surface area and more accessible active sites on the flexible anode. Benefiting from the 3D network with excellent conductivity and stability, at high current densities, the MnOx-MXene/CNF anode exhibits outstanding electrochemical characteristics. Even after 2000 cycles, a reversible capacity of 1098 mA h g−1 can be obtained at 2 A g−1 with only 0.007208% decay rate. The MnOx-MXene/CNF anode also shows a significant rate performance such as 1268 mA h g−1 at 2 A g−1 and 1137 mA h g−1 at 5 A g−1 corresponding to an area specific capacity of 2.536 mA h cm−2 at 4 mA cm−2 and 2.274 mA h cm−2 at 10 mA cm−2, respectively. The results indicate that the MnOx-MXene/CNF anode has excellent Li-ion storage properties and great commercial potential. [ABSTRACT FROM AUTHOR]

Upgrading the energy density and cycling life of current lithium ion batteries is urgently needed for developing advanced portable electronics and electric vehicles. Amorphous transition metal oxides (TMO) with inherent lattice disorders exhibit enormous potential as electrode materials owing to their high specific capacity, fast ion diffusion, and excellent cyclic stability. Yet, challenges remain in their controllable synthesis. In this study, the amorphous phase is induced into α-MoO3 crystal nanobelts at room temperature with the aid of Jahn–Teller effect via enhanced lattice distortion triggered by the accumulation of low-valent molybdenum centers. The optimized HI-MoO3-36 h exhibits high reversible capacities of 886.0 at 0.1 A g−1 and 491.1 mA h g−1 at 1.0 A g−1, respectively, along with outstanding stability retaining 83.4% initial capacity after 100 cycles at 0.1 A g−1. The crystal engineering strategy proposed in this work is believed to be a salutary reference towards the synthesis of high-performance TMO anodes for energy storage applications. [ABSTRACT FROM AUTHOR]

Octahydrate of tetralithium salt of calix[4]arenesulfonic acid was isolated for the first time. The crystal structure of the salt was determined by X-ray diffraction analysis. Compound crystallized in a triclinic syngony, P1¯, a = 11.8752(5) Å, b = 12.2144(4) Å, c = 13.2972(6) Å, α = 97.241(3)°, β = 99.345(4)°, γ = 90.658(3)°, V = 1886.96(13) Å3, Z = 2, R1 = 0.0407, T = 150 K. The presence of 8 water molecules in the structure was confirmed by STA. According to the IR spectroscopy data upon lithiation, the contours of the νs(SO3) and νas(SO3) bands became symmetric and narrower, which was explained by the disappearance of contacts between the sulfonic groups and the H5O2+ cations compared with calix[4]arenesulfonic acid. Lithium ions were qualitatively determined from the maximum of the stretching vibration band of the Li–O bond at ∼400 cm−1. The participation of H2O molecules coordinated by Li cations in the formation of a network of hydrogen bonds with oxygen atoms of sulfogroups was determined by the maximum of the stretching band ν(OH) belonging to these molecules at 3452 cm−1 in the spectrum. The intense band at 3148 cm−1 referred to the ν(OH) stretching vibration of the C–OH group. The dependence of the conductivity of the tetralithium salt of calix[4]arenesulfonic acid in a wide range of humidity has been investigated. It was shown that with the gradual replacement of protons in calix[4]arenesulfonic acid, the conductivity decreased from 10−4–10−2 S cm−1 in acid in the ambient humidity range of 10–60 rel% down to 10−7–10−4 S cm−1 for the tetralithium salt of calixarenesulfonic acid in a wide range of humidity 10–95 rel%. [ABSTRACT FROM AUTHOR]

A facile bottom-up method for the synthesis of lithium titanate nanoplates using a peroxo titanium complex ion precursor is reported. Instead of employing complicated treatment with high alkali concentration, the self-organization reaction between lithium and titanium ions in the prepared ion precursor can enable the formation of layered lithium titanate crystals (Li2−xHxTi2O5, where x = 0.1 and 1.52 for as-synthesise and acid-treated samples, respectively) under low alkaline conditions. We demonstrate that layered lithium titanate crystals can be grown anisotropically into individual nanoplates. Our work presents an easy and useful platform for the production of titanate materials with various morphologies based on the interaction with ionic species. [ABSTRACT FROM AUTHOR]

Fe-Doped ZnFexCo2−xO4 (x = 0.00, 0.17, 0.33, 0.47, 0.67, 0.87, 1.17, 1.37, 1.67, 1.87, 2.00) compounds were prepared by a sol–gel method. X-ray diffraction measurements show that Fe-doping does not change the crystal structure of ZnCo2O4 and dopant Fe successfully occupies the 16c Co site. Because of the bigger radius of the doping ion, the cell parameters and cell volumes of ZnFexCo2−xO4 compounds present an obvious linear increase with increasing Fe content. In addition, attributed to the similar crystal structures for ZnFe2O4 and ZnCo2O4, a full range (0 ≤ x ≤ 2) of ZnFexCo2−xO4 solid solution phases was obtained. V/I measurement results show that a small Fe doping content obviously improved the electronic conductivity of the sample. In addition, due to the smaller particles size and uniform particle distribution caused by Fe doping, the lithium ion diffusion coefficient of the sample was increased by 2 orders of magnitude. Based on the improved electronic conductivity combined with the significantly increased lithium-ion diffusion coefficient, a sample with Fe doping content of x = 0.33, ZnFe0.33Co1.67O4, presents a high reversible specific capacity and excellent rate cycle stability. At a rate of 100 mA g−1, a relatively high discharge capacity of 850 mA h g−1 can still be obtained after 100 cycles, which is obviously higher than that of pure ZnCo2O4 (only 295 mA h g−1). Even at a higher discharge rate of 500 mA g−1, a discharge capacity of 450 mA h g−1 with a capacity retention of nearly 100% was obtained. Based on its excellent electrochemical properties, ZnFe0.33Co1.67O4 will be a promising anode material for rechargeable lithium-ion batteries. [ABSTRACT FROM AUTHOR]

The incorporation of active nitrogen species in carbon materials has been widely demonstrated as a viable means to produce superior lithium storage materials, while the precise regulation of nitrogen configurations as well as their content still remains a formidable challenge. Herein, nitrogen-free porous carbon frameworks were synthesized by a self-templating strategy from disodium citrate, and post-annealing yielded 10.4 at% N that was primarily pyrrolic-N and pyridinic-N with an atomic ratio of about 3 : 1, with negligible inactive graphitic-N. A gravimetric capacity of 570 mA h g−1 at a current density of 4 A g−1 was measured for a Li half-cell based on the as-prepared N-doped 3D carbon materials. Lithium-ion capacitors with this N-doped carbon as the anode and commercial AC as the cathode yielded energy densities of 58.9 and 142.6 W h kg−1 with the corresponding power densities of 7400 and 185 W kg−1, respectively. We suggest that the carbon materials with high content of pyrrolic-N and pyridinic-N especially pyrrolic-N have improved lithium storage. [ABSTRACT FROM AUTHOR]

Here, a poly(vinylidene fluoride) (PVDF)-based composite polymer electrolyte (CPE) with a unique Li0.33La0.56TiO3 (LLTO) nanotube filler, which shows a high Li-ion conductivity, is reported. Compared with LLTO nanoparticles (NPs) and nanowires (NWs), the LLTO nanotube fillers increase the interfacial area between PVDF and the LLTO filler, leading to the simple transportation of Li-ions through these interfacial pathways. In addition, the Li plating and stripping cycling performance of the CPEs is improved to 205 h at 0.1 mA cm−2, and the performance of the Li‖CPEs‖LiFePO4 cells also achieves a discharge capacity of 120 mA h g−1 after 100 cycles at 0.5C at room temperature. These results demonstrate an effective interfacial strategy for the design of high Li-ion conduction CPEs for all solid-state batteries. [ABSTRACT FROM AUTHOR]

In order to develop novel fast charge/discharge carbon anode materials, an organic hard carbon material (PTCDA-1100) is obtained by calcination of perylene-3,4,9,10-tetracarboxylic dianhydride (PTCDA) at a high temperature of 1100 °C. The obtained PTCDA-1100 sample has a disordered porous nanostructure, large specific surface area, and more exposed active points, providing channels for the rapid transport of lithium ions. As a result, the PTCDA-1100 electrode shows superior lithium storage behavior compared to conventional commercial graphite materials when used as a negative anode material for lithium-ion batteries. When the PTCDA-1100 electrode is charged and discharged at the small current rate of 0.2C, the initial capacity of the electrode is 320.7 mA h g−1, which is very close to that of graphite (329.5 mA h g−1). However, as the cycles increase, after 100 cycles, the capacity of the PTCDA-1100 electrode is 290.9 mA h g−1 with a retention rate of 90.7%, which are significantly higher than the capacity of graphite (231.3 mA h g−1) and its retention rate of 70.2%. Similarly, at all other high current rates of 1C, 3C and 5C, the PTCDA-1100 electrode is significantly better in both capacity and cycle stability than the commercial graphite electrode. Overall, the PTCDA-1100 organic hard carbon materials prepared in this work show better cyclic stability and rate capability both in half and full batteries compared to commercial graphite material, which would provide new ideas for developing novel carbon negative materials for fast charge and discharge of lithium-ion batteries. [ABSTRACT FROM AUTHOR]

Cerium dioxide nanocrystals embedded in porous carbon rod materials were used for sulfur storage and embedding. Polar cerium dioxide effectively adsorbed polysulfide and inhibited the shuttle effect. By calculating the diffusion coefficient of the lithium-ions, it was concluded that the porous carbon rod material with cerium oxide was beneficial for the rapid binding of lithium ions and sulfur. [ABSTRACT FROM AUTHOR]