The development of safe, stable, and long-life Li-ion batteries is being intensively pursued to enable the electrification of transportation and intelligent grid applications. Here, we report a new solid-state Li-ion battery technology, using a solid nanocomposite electrolyte composed of porous silica matrices with in situ immobilizing Li+-conducting ionic liquid, anode material of MCMB, and cathode material of LiCoO2, LiNi1/3Co1/3Mn1/3O2, or LiFePO4. An injection printing method is used for the electrode/electrolyte preparation. Solid nanocomposite electrolytes exhibit superior performance to the conventional organic electrolytes with regard to safety and cycle-life. They also have a transparent glassy structure with high ionic conductivity and good mechanical strength. Solid-state full cells tested with the various cathodes exhibited high specific capacities, long cycling stability, and excellent high temperature performance. This solid-state battery technology will provide new avenues for the rational engineering of advanced Li-ion batteries and other electrochemical devices.

The nickel-rich LiNi0.7Co0.15Mn0.15O2 material was sintered by Li source with the Ni0.7Co0.15Mn0.15(OH)2 precursor, which was prepared via hydrothermal treatment after coprecipitation. The intensity ratio of I(110)/I(108) obtained from X-ray diffraction patterns and high-resolution transmission electronmicroscopy confirm that the particles have enhanced growth of (110), (100), and (010) surface planes, which supply superior inherent Li+ deintercalation/intercalation. The electrochemical measurement shows that the LiNi0.7Co0.15Mn0.15O2 material has high cycling stability and rate capability, along with fast charge and discharge ability. Li+ diffusion coefficient at the oxidation peaks obtained by cyclic voltammogram measurement is as large as 10–11 (cm2 s–1) orders of magnitude, implying that the nickel-rich material has high Li+ diffusion capability.Keywords: cycling stability; Li+ transportation; lithium-ion batteries; nickel-rich layered material; rate capability

Three Mg-enriched engineered carbons (mesocarbon microbeads, MCMB) were produced from lithium-ion battery anode using concentrated nitric acid oxidization and magnesium nitrate pretreatment. The obtained 15%Mg-MCMB, 30%Mg-MCMB, and 40%Mg-MCMB have magnesium level of 10.19, 19.13, and 19.96%, respectively. FTIR spectrum shows the functional groups present on the oxidized MCMB including OH, C═O, C–H, and C–O. XRD, SEM-EDX, and XPS analyses show that nanoscale Mg(OH)2 and MgO particles were presented on the surface of the Mg-MCMB samples, which could serve as the main adsorption mechanism as to precipitate phosphate from aqueous solutions. The sorption experiments indicate that Mg modification dramatically promotes MCMB’s phosphate removal ability and phosphate removal rates reach as high as 95%. Thus, modification of the spent LIBs anode could provide a novel direction of preparing wastewater adsorbent and develop an innovative way to achieve sustainable development.Keywords: adsorption; magnesium; mesocarbon microbeads; phosphate; spent battery;

A novel approach was used to prepare engineered biochar from biofuel residue (stillage from bagasse ethanol production) through slow pyrolysis. The obtained biochar was characterized for its physicochemical properties as well as silver sorption ability. Sorption experimental data showed that engineered biochar quickly and efficiently removed silver ion (Ag+) from aqueous solutions with a Langmuir maximum capacity of 90.06 mg/g. The high sorption of Ag+ onto the biochar was attributed to both reduction and surface adsorption mechanisms. The reduction of Ag+ by the biochar was confirmed with scanning electron microscopy, energy-dispersive X-ray spectroscopy, X-ray diffraction, and X-ray photoelectron spectroscopy analyses of the postsorption biochar, which clearly showed the presence of metallic silver nanoparticles on the surface of the carbon matrix. An antimicrobial ability test indicated that silver-laden biochar effectively inhibited the growth of Escherichia coli, while the original biochar without silver nanoparticles promoted growth. Thus, biochar, prepared from biofuel residue materials, could be potentially applied not only to remove Ag+ from aqueous solutions but also to produce a new value-added nanocomposite with antibacterial ability.Keywords: biochar; biofuel residue; engineered carbon; nanocomposite; silver;

Two types of hard carbon materials were synthesized through direct pyrolysis of commercial polyvinyl chloride (PVC) particles and pyrolysis of PVC nanofibers at 600–800 °C, respectively, where the nanofibers were prepared by an electrospinning PVC precursors method. These as-prepared hard carbon samples were used as anode materials for Na-ion batteries. The hard carbon obtained from PVC nanofibers achieved a high reversible capacity of 271 mAh/g and an initial Coulombic efficiency of 69.9%, which were much superior to the one from commercial PVC, namely, a reversible capacity of 206 mAh/g and an initial Coulombic efficiency of 60.9%. In addition, the hard carbon originated from the PVC nanofibers exhibited good cycling stability and rate performance: the initial discharge capacities were 389, 228, 194, 178, 147 mAh/g at the current density of 12, 24, 60, 120, and 240 mA/g, respectively, retaining 211 mAh/g after 150 cycles. Such excellent cycle performance, high reversible capacity, and good rate capability enabled this hard carbon to be a promising candidate as anode material for Na-ion battery application.Keywords: electrospinning; hard carbon; Na-ion battery; polyvinyl chloride nanofiber

•Review advances in nanomaterials synthesis from biomass for rechargeable batteries.•Discuss some of the key factors that limit such rechargeable battery performance.•Present how to use biomass/bionics to develop high-performance battery materials.•Highlight the underline rationale to use these approaches.The ultimate goal of materials design and development is to come up with the best large-scale performance with proper structure and composition modification of individual building blocks. Bionics is gradually becoming the research focus as it signifies a promising strategy to make materials with generated structures having true three-dimensional order and multiple contributions to the bulk properties. In this article, we review advances in synthesis of nanostructured materials for developing high performance rechargeable batteries using biomass/bionic approaches. Understanding and mitigating some of the key factors that limit such rechargeable battery performance will also be briefly presented. We present a few examples to demonstrate how the biomass/bionics can be used to develop high-performance battery materials, and especially, highlight the underline rationale to use these approaches. Our hope is that the concepts and results presented in this article will prompt new researchers to join this field and help broaden the scope and impact of rechargeable batteries using the materials from biomass.

•First principle is used to calculate the density of states of Fe(1−x)TixF3.•The effect of Ti-dopant on the microcrystal growth of Fe(1−x)TixF3 is evaluated.•A synergic-antergic mechanism is put forward to expound the combined effects.•Fe0.99Ti0.01F3/C nanocomposite shows a high capacity of 219.8 mA h/g in 2.0–4.5 V.•The three-electron reaction of Fe(1−x)TixF3 achieves 764 mA h/g in 1.0–4.5 V.Whether FeF3 can take active part in electrochemical reaction is largely determined by its conductivity, which can be affected by the band gap and crystallite dimension. In this communication, the density of states (DOS) of FeF3 and Ti-doped FeF3 were calculated using a first principle density functional theory (DFT). Moreover, crystalline size was calculated according to Debye-Scherrer Equation. The results indicate that Ti-doping can reduce the band gap and impact the microcrystal growth of FeF3 at the same time. Both effects work synergistically on capacity loss and cycling stability; while impact antagonistically on charge transfer resistance (Rct), Li+ diffusion coefficient (DLi+) and specific capacity, leading to the excellent electrochemical performances of Fe(1−x)TixF3/C. The Fe0.99Ti0.01F3/C nanocomposite achieves an initial capacity of 219.8 mA h/g and retains a discharge capacity of 173.6 mA h/g after 30 cycles at room temperature in the voltage range of 2.0–4.5 V. The hysteresis of discharge voltage plateau is significantly mitigated as well. In addition, the three-electron reaction of Fe0.99Ti0.01F3/C during 1.0–4.5 V exhibits a high initial specific discharge capacity of 764.6 mA h/g. This study suggests that not only the band gap, but also the microcrystalline structure can be changed by Ti-doping, both of which have remarkable effects on the electrochemical properties, providing a new perspective on the effect of cation dopant.

•Hierarchical cathode Li[Li0.2Ni0.2Mn0.6]O2 was coated with LiF/FeF3 layer.•A combination of conversion reaction and extraction/insertion reaction was explored.•LiF/FeF3 layer with different coating thickness exhibited respective merits.•Superior rate performance was obtained with an ultrathin layer.•A significantly improved cycling performance was realized with a thicker layer.Advanced lithium-ion batteries for renewable energy storage applications have become a major research interest in recent years. Much better performance can be realized by improvements in the material surface design, especially for the cathode materials. Here, we present a new design for a surface protective layer formed via a facile aqueous solution process in which a nano-architectured layer of LiF/FeF3 is epitaxially grown on bulk hierarchical Li-rich cathode Li[Li0.2Ni0.2Mn0.6]O2. Coin cell tests of this material in the voltage range of 2–4.8 V indicated a high reversible capacity (260.1 mA h g−1 at 0.1 C), superior rate performance (129.9 mA h g−1 at 20 C), and excellent capacity retention. Differential scanning calorimetry showed good thermal stability. The enhanced capacity and cycling stability are attributed to the suppression of interfacial side reactions as well as the conversion reaction resulting from the introduction of LiF/FeF3 as a surface protective layer.

As the most promising cathodes of lithium-ion batteries, lithium-rich manganese-based layered oxides with high capacity suffer from poor cycle stability, poor rate capability, and fast voltage fading. Here we introduced AlF3 into the surface of layered lithium-rich cathode (Li[Li0.2Fe0.1Ni0.15Mn0.55]O2) as an artificial protective layer as well as an inducer of integrated layered-spinel structures to achieve both low cost and high capacity. The reduced irreversible capacity loss, improved cycling stability, and superior high-rate capability were ascribed to the combination of AlF3 nanocoating and the unique structures as well as the low charge transfer resistance. Besides, the intractable issue, fast voltage fading of the layered lithium-rich cathode was also alleviated. Such materials with both low cost and high capacity are considered to be promising candidate cathodes to achieve lithium-ion batteries with high energy and high power.Keywords: AlF3; layered-spinel; lithium-ion batteries; nanocoating; phase transformation

•We report a new electrolyte system based on LiODFB and DMS.•LiODFB–EC/EMC/DMS electrolyte forms a stable SEI film on MCMB electrode.•The reversible capacity is as high as 222.4 mAh g−1 at 1C.Lithium difluoromono(oxalato)borate (LiODFB) has been used as a novel lithium salt for battery in recent studies. In this study, a series of novel electrolytes has been prepared by adding 30 vol% dimethyl sulfite (DMS) or dimethyl carbonate (DMC) as co-solvent into an ethylene carbonate (EC)/ethyl methyl carbonate (EMC) + LiX mixture, in which the LiX could be LiClO4, LiODFB, LiBOB, LiTFSI, or LiCF3SO3. These ternary electrolytes have been investigated for use in lithium ion batteries. FT-IR spectroscopy analysis shows that characteristic functional groups (–CO3, –SO3) undergo red-shift or blue-shift with the addition of different lithium salts. The LiODFB–EC/EMC/DMS electrolyte exhibits high ionic conductivity, which is mainly because of the low melting point of DMS, and LiODFB possessing high solubility. The Li/MCMB cells containing this novel electrolyte exhibit high capacities, good cycling performance, and excellent rate performance. These performances are probably because both LiODFB and DMS can assist in the formation of SEI films by reductive decomposition. Additionally, the discharge capacity of Li/LiCoO2 half cell containing LiODFB–EC/EMC/DMS electrolyte is 130.9 mAh g−1 after 50 cycles, and it is very comparable with the standard-commercial electrolyte. The results show that this study produces a promising electrolyte candidate for lithium ion batteries.

A leaching process for the recovery of cobalt and lithium from spent lithium-ion batteries (LIB) is developed in this work. Three different organic acids, namely citric acid, malic acid and aspartic acid, are used as leaching reagents in the presence of hydrogen peroxide. The cathode active materials before and after acid leaching are characterized by X-ray diffraction and scanning electron microscopy. Recovery of cobalt and lithium is optimized by varying the leachant and H2O2 concentrations, the solid-to-liquid ratio, and the reaction temperature and duration. Whereas leaching with citric and malic acids recovered in excess of 90% of cobalt and lithium, leaching with aspartic acid recovered significantly less of these metals. The leaching mechanism likely begins with the dissolution of the active material (LiCoO2) in the presence of H2O2 followed by chelation of Co(II) and Li with citrate, malate or aspartate. An environmental analysis of the process indicates that it may be less energy and greenhouse gas intensive to recover Co from spent LIBs than to produce virgin cobalt oxide.Highlights► A leaching process for the recovery of cobalt and lithium from LIBs was developed. ► Citric and malic acids are more effective as leaching reagents than aspartic acid. ► An environmental assessment was conducted to examine its energy consumption. ► An environmental analysis predicts a FFC energy intensity of recovered Co. ► The technical process is promising and economic with environmental merits.

Recycling of the major components from spent Li-ion batteries (LIBs) is considered desirable to prevent environmental pollution and recycle valuable metals. The present work investigates a novel process for recovering Co and Li from the cathode materials (containing LiCoO2 and Al) by a combination of ultrasonic washing, calcination, and organic acid leaching. Copper can also be recovered from the anode materials after they are manually separated from the cathode. Ascorbic acid is chosen as both leaching reagent and reducing agent to improve the Co recovery efficiency. Leaching efficiencies as high as 94.8% for Co and 98.5% for Li are achieved with a 1.25 mol L−1 ascorbic acid solution, leaching temperature of 70 °C, leaching time of 20 min, and solid-to-liquid ratio of 25 gL−1. The acid leaching reaction mechanism has been preliminarily studied based on the structure of ascorbic acid. This method is shown to offer an efficient way to recycle valuable materials from spent LIBs, and it can be scaled up for commercial application.Highlights► We report an ultrasonic-assisted hydrometallurgical technique. ► Ascorbic acid is chosen as both leaching reagent and reducing agent. ► This technique avoids use of the traditional reducing agent H2O2. ► Leaching efficiencies are as high as 94.8% for Co and 98.5%. ► The acid leaching reaction mechanism has been preliminarily studied.

A novel method has been applied to the surface modification of the metal hydride (MH) electrode of the MH/Ni batteries. Both sides of the electrode were plated with a thin cobalt film about 0.15 μm using vacuum evaporate plating technology and the effect of the electrode on the performance of the MH/Ni batteries was examined. It was found that the surface modification could enhance the electrode conductivity and decrease the battery ohmic resistance. After surface modification, the discharge capacity at 5C (8.5 A) was increased by 115 mAh and discharge voltage was increased by 0.04 V, the resistance of the batteries was also decreased by 18%. The batteries with modified electrode exhibited satisfactory durability. The remaining capacity of the modified batteries was 93% of the initial capacity even after 500 cycles. The inner pressure of the batteries during overcharging was lowered and the charging efficiency of the batteries was improved.

The catalyst, Ni nano-particles supported on Y2O3, which was prepared by three methods, was studied. The structural properties of the catalysts were tested through X-ray diffraction and BET area. The catalyst of Ni/Y2O3 exhibits high activity for ethanol steam reforming with conversion of ethanol of 98% and selectivity of hydrogen of 38% at 300°C, conversion of ethanol of 98% and selectivity of hydrogen of 55% at 380°C. With temperature increasing to and above 500°C, the conversion of ethanol increased to 100%, but the selectivity of hydrogen did not increase so much, it was 58% at 600°C. The catalyst has long-term stability for steam reforming of ethanol and is a good choice for ethanol processors for fuel cell applications.

As a new type of multi-electron transfer device, rechargeable aluminum batteries are promising post-lithium ion batteries owing to their high theoretical energy density. However, it is unknown whether Al3+ can be reversibly stored in the lattice of the host electrode material because of its small cation diameter and high valence state, thus trapping it tightly in lattice or defect sites. Here, we report the reversible storage of Al3+ in V2O5 nanowires. It is found that Al3+ intercalates into crystalized V2O5 nanowires in the first discharge. Meanwhile, this electrochemical intercalation leads to the reduction of V5+ and the formation of an amorphous layer on the edge of nanowires. In the subsequent cycling, a new phase forms along the nanowires’ edges and a two-phase transition reaction occurs. Our findings demonstrate clearly for the first time that it is possible that Al3+ can be inserted into the metal oxide and stored reversibly through intercalation and a phase-transition reaction, which is expected to inspire more comprehensive investigations for rechargeable aluminum batteries.Our findings demonstrate clearly for the first time that Al3+ can insert into the metal oxide reversibly through intercalation and phase transition reaction. The electrochemical insertion and extraction of Al3+ lead to redox of V2O5. Insertion and extraction of Al3+ in V2O5 nanowire result in structure change on the crystalized V2O5 nanowires. Amorphous layers and new phase form along the V2O5 nanowires’ edge during electrochemical reaction.Download high-res image (510KB)Download full-size image