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Energy storage devices (ESD) which are intended to power electronic devices, used in close contact of human skin, are desirable to be safe and non-toxic. In light of this requirement, Zn based energy storage devices seem to provide a viable pathway as they mostly employ aqueous based electrolytes which are safe and non-toxic in their functioning. Additionally, having a flexible ESD will play a crucial role as it will enable the ESD to conform to the varying shapes and sizes of wearable electronics which they energize. In this work, we have developed an inkjet-printed Zinc ion battery (IPZIB) with planar electrode configuration over bond paper substrate. Zn has been used as the negative electrode, MnO2 is used as the positive electrode with Poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) as the active binder. Conducting tracks of reduced graphene oxide (rGO) are used to construct the current collector on the paper substrate. The fabricated IPZIB delivered a high discharge capacity of 300.14 mAh g−1 at a current density of 200 mA g−1. The energy density of the IPZIB is observed as 330.15 Wh kg−1 at a power density of 220 W kg−1 and retains an energy density of 94.36 Wh kg−1 at a high power density of 1650 W kg−1. Finally, we have demonstrated the capability of the IPZIB to power a LED at various bending and folding conditions which indicates its potential to be used in the next generation flexible and wearable electronic devices. [ABSTRACT FROM AUTHOR]

Wearable electronic energy storage devices usually require the integration of flexible mechanisms and uncompromising electrochemistry of lithium-ion batteries (LIBs). Most of the studies in this field have mainly focused on enhancing the electrochemical properties of the material, while the significance of its flexibility and mechanical properties has been relatively ignored. In this study, the 20 wt % carbon fibers (CFs) composite N-doped flexible carbon nanofiber paper (NFCFP) was prepared through a facile PFI refiner and Bauer sieve of pulping and papermaking machinery sieve-assisted methods combined with annealing technology. The NFCFP-700 with high pyridine N content shows good ion transport and storage performance, the specific capacity remained 308 mAh⸱g−1 after 100 cycles at 0.1 C, and even at 1 C, the specific capacity of the electrode material instead increases constantly at 142 mAh⸱g−1. According to density functional theory (DFT) calculations, the coexistence of pyridine N content and defects in carbon materials was found to enhance the adsorption energy (E ad) of lithium, and the N4V2 locally show the most negative electrostatic potential (ESP) distribution, which was more favorable for the adsorption of Li+ being positively charged. This insight from DFT studies combined with experimental data emphasizes the favorable impact of pyridine N content and defects on the lithium adsorption process in carbon materials, also providing valuable information for the design and optimization of materials for lithium storage applications. [ABSTRACT FROM AUTHOR]

We synthesized a flexible lithium-ion battery (LIB) anode with a flower-like CuCo2O4 nanostructure grown on the surface of conductively-treated filter paper. The filter paper, made of cotton fibers, has good flexibility, but its poor conductivity limits its application in flexible electrodes. An Ni coating by magnetron sputtering can significantly improve its conductivity, which enables it to be used as a substrate for flexible electrodes. The flower-like CuCo2O4 nanostructure is assembled from CuCo2O4 nanowires with a diameter of 50 nm, while the CuCo2O4 nanowires are assembled from CuCo2O4 nanoparticles with a size of 10–20 nm. The gap between the stacked CuCo2O4 nanoparticles causes the porous structure of the CuCo2O4 nanowires. The high theoretical capacity of CuCo2O4, the porous structure of the CuCo2O4 nanowires, and the tiny CuCo2O4 nanoparticles lead to the excellent electrochemical performance of the CuCo2O4 flower-like nanostructure. It maintains capacity very well during cycling and delivers a high capacity of 989 mAh g−1 at a current density of 100 mA g−1. As a flexible LIB anode, the composite with the flower-like CuCo2O4 nanostructure grown on the surface of conductively-treated filter paper delivers a stable capacity of 544 mAh g−1 at a current density of 100 mA g−1 and a capacity of 304 mAh g−1 at a high current density of 2000 mA g−1. The conductively-treated filter paper substrate can significantly improve the battery property of the hydrothermally-fabricated CuCo2O4. [ABSTRACT FROM AUTHOR]

Cellulose is now considered as an appealing environment friendly material for the development of sustainable separators for rechargeable batteries. This study thus aims to develop high performance paper based ceramic separators with superior electrolyte wettability (>170 %), high thermal stability (>200 °C) and excellent flame safety. While developing paper based ceramic separator, extensive studies are carried out to understand thenature and functionality of different nano-structured ceramic materials (Al 2 O 3 , BaTiO 3 and ZrO 2) impregnated in paper matrix. Nano-ZrO 2 facilitates an effective pathway for Li +-ion transport (t Li + = 0.51), whereas BaTiO 3 and Al 2 O 3 ceramics show moderate Li +-ion transport properties (t Li+ of 0.29 and 0.30 respectively). Electrochemical Impedance Spectroscopy (EIS) measurement clearly reveals that ZrO 2 exhibits more interfacial compatibility with the electrodes (MCMB and LiNi 1/3 Mn 1/3 Co 1/3 O 2) compared to the other two ceramic separators during full cell operation. The developed paper separators show excellent electrochemical properties in terms of cycling (tested 300 cycles), multi-electrode compatibility and rate capabilities at different current densities of 0.1–1.2 mAcm−2. The pre- and post-electrochemical EIS data reveal that ZrO 2 based impregnation offers significantly lower charge transfer resistance compared to the other two separators. The study thus demonstrates a real promise for its successful application in Li-ion battery towards achieving sustainability and safety. [Display omitted] • Sustainable, flexible and high safety ceramic based paper separators for LIBs. • Separators were developed using easy to scale up wet-coating process. • Ceramic impregnation affects physical and electrochemical properties of the separators. • Paper separators show superior electrolyte wettability and high thermal stability. • Better electrochemical performances and flame safety are other important advantages. [ABSTRACT FROM AUTHOR]

MoO 3 -based anodes for lithium storage have attracted more attentions due to the relatively high specific capacity of 1117 mAh g–1 and good chemical stability. Compound MoO 3 with other functional materials and construction of unique micromorphologies have been proved to be efficient strategies for improving the electrochemical performances of MoO 3 -based anodes. Herein, MoO 3 /TiO 2 composites were successfully biosynthesized with different micromorphologies. In the preparation processes, the hydrothermal and solvothermal treatments were carried out successively in the presence of cellulosic filter paper as the biotemplate, followed by calcination of the as-obtained composites in air, resulting in the final MoO 3 /TiO 2 composite materials. The two microstructures of the MoO 3 microfiber with entire TiO 2 nanoparticles coating and the MoO 3 microrod formed by stacking the microsheets with loosely TiO 2 nanoparticles covering were prepared under different pH values of the precursor. Compared with the bare MoO 3 materials, the corresponding MoO 3 /TiO 2 composites showed enhanced electrochemical performances as anode materials for lithium-ion batteries. Especially the MoO 3 /TiO 2 composite with core-shell microfibrous structure derived from cellulosic filter paper presented relatively better test results for lithium storage, delivering an initial discharge capacity of 1297.6 mAh g−1 with the first Coulombic efficiency of 65.8%, and a reversible specific capacity of 403.6 mAh g−1 after 200 cycles. It is demonstrated that a well-defined TiO 2 coating layer can effectively inhibit the volume variations of MoO 3 matter in the lithiation/delithiation processes. Combined with the porous microfibrous structure that alleviates the stress, provides more reaction sites and reduces diffusion paths of lithium-ion, a promising MoO 3 -based anode material was achieved. This work provides a facile biotemplate-based strategy for the design and fabrication of metal oxide-based composites with adjustable microstructures for energy storage. [Display omitted] • Cellulosic filter paper derived MoO 3 /TiO 2 composites with variable micromorphologies were biosynthesized. • Microfibrous MoO 3 was coated by TiO 2 nanoparticles uniformly using the precursor with original pH value. • It showed enhanced reversible capacity, cycling stability and rate capability as an anode material for lithium-ion batteries. • The microstructural feature of biotemplate and the entire TiO 2 coating contribute to the improved lithium storage property. [ABSTRACT FROM AUTHOR]

Freestanding tin oxide-boron oxide/reduced graphene oxide (SnO2-B2O3/rGO) nanocomposite anode was produced for Li-ion cells. This binder-free flexible paper anode structure was fabricated by combining SnO2-B2O3 composite and graphene oxide which were synthesized through the sol–gel method and Hummers’ method, respectively. Field emission gun scanning electron microscopy, high-resolution transmission electron microscopy, energy dispersive X-ray spectrometer, Fourier transform infrared spectroscopy, Raman spectroscopy, and X-ray diffraction were utilized to characterize anode materials. The Williamson-Hall (W-H) analysis was applied using XRD data to determine crystal size and strain of the lattice. Electrochemical tests, cyclic voltammetry, and electrochemical impedance spectroscopy measurements were performed to determine electrochemical properties of the anodes. The results indicated that the anode formed with SnO2-B2O3 particles anchored on the rGO layers provided higher discharge capacity (838 mAhg-1) than that of SnO2/rGO (395 mAh g-1) after 100 cycles. The electron-deficient nature of boron supplied an effective increase in electrochemical energy storage performance. [ABSTRACT FROM AUTHOR]

The paper describes the digital twin of a Li-ion battery cell based on the MATLAB/Simulink generic model. The digital twin is based on measured data for constant current/constant voltage charging and discharging cycles with State of Health (SoH) up to 79%, also including fast charging. Mathematical equations used for the digital twin are obtained by 3D data fitting of measured SoH, battery capacity, and battery cell current. The input to the proposed digital twin is only the measured battery cell current, and its output includes State of Charge (SoC), SoH, and battery cell voltage. The designed digital twin is tested and compared with MATLAB/Simulink generic model and battery cell measurements for constant discharging current and dynamically generated discharging current profile. The results show significant improvement in the generic MATLAB/Simulink model. [ABSTRACT FROM AUTHOR]

Until recently, lead-acid batteries were the go-to source for storing energy for UPS/Inverter applications. The most common types of batteries used in wind applications are Valve-Regulated Lead-Acid batteries (VLRAs). But, lead-acid batteries have drawbacks that make them risky and expensive to use in wind turbine applications. They are the element that is most likely to fail at the moment when they are most needed. It is hard enough to deploy and manage lead-acid batteries traditionally. But when VRLAs are used in remote facilities, there are some problems that increase the effort and the cost of using them. Currently, the Soweto Small Wind Turbine is incorporated with the Vertiv (Inverter) and VRLA battery type. TP 100 Vision lithium iron phosphate (LiFePO4) batteries offer substantial advantages. This battery system is ideal for both UPS/Inverters and energy storage systems, offering excellent compatibility and a secure, durable lifespan. Factory testing was carried out on the installation and testing of a TP 100 Vision battery to a Vertiv-type UPS at a South African company. A variable resistive load bank was added to the UPS output in order to test and evaluate the outcome. This paper presents the factory testing results and proposes the implementation of the TP100 Vision battery to a 500W Small Wind Turbine (SWT) in Soweto, Johannesburg, South Africa. [ABSTRACT FROM AUTHOR]

A filter-paper-derived nanofibrous silica–carbon composite composed of thin silica layer conformally coated on carbon nanofibers is synthesized by employing natural cellulose substance (ordinary laboratory filter paper) as both scaffold and carbon source. When the nanocomposite is employed as an anode material for lithium-ion batteries, it displays improved lithium-ion storage performance compared with the bare silica and carbon counter materials, due to the unique three-dimensional porous network structures of the carbon fiber scaffold and the thin silica layer. For the silica–carbon nanocomposite with 31.2 wt% of silica content and the silica layer with a thickness of ca. 60 nm, it delivers a stable discharge capacity of ca. 400 mAh g −1 after 200 discharge/charge cycles at a current density of 100 mA g −1 . Moreover, improved electrochemical performances are achieved by coverage of an additional carbon layer or deposition of silver nanoparticles onto the silica–carbon nanofibers, which exhibits specific capacities of 488.7 and 477.5 mAh g −1 after 100 discharge/charge cycles, respectively. The current synthetic method provides a facile and low-cost strategy for the large-scale production of nanofibrous silica–carbon based composites as anodic materials for lithium-ion batteries. [ABSTRACT FROM AUTHOR]

Abstract A facile one-step solid-phase synthesis strategy is developed for synthesizing a binder-free molybdenum disulfide/carbon fibers paper (MoS 2 /CFP) anode. The microstructure, composition, morphology and electrochemical performances were investigated. It is found that the thin MoS 2 layers are well anchored on the interlaced carbon fibers to form MoS 2 /CFP, which has mesoporous structure and large specific surface area of ∼18.8 m2g-1. As a result, the obtained MoS 2 /CFP anode exhibits a reversible capacity of 261 mAh·g−1 with 31.2% loading ratio of MoS 2. After subtracting the capacity of CFP, the MoS 2 in the composite anode delivers a reversible capacity of 539 mAh·g−1 and shows better cycle stability than commercial MoS 2 after 100 cycles at 100 mA g−1. The remarkable electrochemical performances could be attributed to the buffer space among carbon fibers for the volume changes of MoS 2 as well as the highly conductive carbon fibers network, suggesting that the MoS 2 /CFP is a promising binder-free anode for lithium-ion batteries. Graphical abstract Image 1 Highlights • A one-step solid-phase synthesis strategy is developed to fabricate MoS 2 /CFP anode. • The MoS 2 and the carbon matrix of MoS 2 /CFP composite were synthesized synchronously. • The MoS 2 /CFP anode exhibits enhanced cycling performance and high-rate capability. • The mechanism of the enhanced electrochemical properties was discussed for MoS 2 /CFP. [ABSTRACT FROM AUTHOR]

This paper defines terms such as "recycling rate" that enable the characterization of flows of battery materials and expands the terminology to accommodate the description of complex product recycling. It also estimates the maximum percentage of U.S. demand for critical elements that could be satisfied by recycling as demand continues to grow, and it defines and estimates the recycling rate for lithium-ion batteries. Finally, it clarifies the role of manufacturing scrap as the domestic U.S. supply chain is built up. It concludes that recycling will be important in the long term, but growth still requires that new material be extracted to supply additional material. [ABSTRACT FROM AUTHOR]

To improve the electrochemical performance of Si-based lithium ion batteries, a novel multilayer microporous three-dimensional porous carbon nanosheet (PC)/multi-walled carbon nanotube (MWCNT) (PM) composite unbonded paper fiber current collector was used to replace copper foil. PM combines the advantages of PC and MWCNTs. MWCNTs provide a good conductive path that promotes electron transport and maintains structural integrity. The three-dimensional interconnected structure of one-dimensional MWCNTs combined with two-dimensional porous PC facilitates rapid electrical/ion transport and good electrolyte penetration. Moreover, PM has a tiny nanostructure. PM is filled, adsorbed and aggregated in the surface of the paper fiber and the gaps between the paper fiber and the paper fiber, which acts to connect the paper fibers and the carrier. The paper fiber has a natural non-agglomerate advantage so that PM/paper fiber (PMP) shows excellent physical properties. The initial coulombic efficiency of the Si-PMP electrode reached 69.3% and maintained a specific discharge capacity of 755 mAh/g at a current density of 0.08 A/g with a capacity retention ratio of 65.2% after 200 cycles. [ABSTRACT FROM AUTHOR]

Repressing the hampers of poor electrical conductivity and pulverization is central for the applications of metal oxides anode materials, yet remains big challenge. To meet the target, pie-like graphene paper@Fe 3 O 4 nanorod arrays@carbon film is designed and fabricated as high-performance integrated electrode for lithium ion batteries. Graphene paper is selected as binder-free integrated substrate, which could accelerate electron transfer, buffer volume changes of Fe 3 O 4 , contribute to additional capacity, and endow the electrode with flexibility. The carbon film serves as the package to prevent the dissolution of Fe 3 O 4 into the electrolyte, extending the cyclic life of the integrated electrode. The architecture of Fe 3 O 4 nanorod array offers void space for volume buffer and fluid electrolyte infiltration. Based on the combined structural advantages, the present pie-like electrode with interior array architecture therefore exhibits excellent electrochemical lithium storage properties, especially large, stable, and durable cyclic performance at high current density (852 mA g −1 after 1000 cycles at 2 A g −1 ), making it a promising candidate as high-performance flexible electrode. [ABSTRACT FROM AUTHOR]

A flexible, lightweight, and high conductivity current collector is the key element that enables fabrication of a high-performance, flexible lithium-ion battery. Here, we report a thin, lightweight, and flexible lithium-ion battery that uses graphite papers deposited with nano-sized metallic layers as the current collector, LiFePO4 and Li4Ti5O12 as the cathode and anode materials, respectively, and a PE membrane soaked in LiPF6 as the separator. Using thin, flexible graphite paper as a substrate for the current collector instead of a rigid, heavy metal foil enables us to demonstrate an ultra-thin lithium-ion battery (total thickness including encapsulation layers of less than 250 μm) that also features a light weight and high flexibility. [ABSTRACT FROM AUTHOR]

A user-friendly, low-cost detector able to read the RGB indexes of microfluidic paper-based analytical devices (µPADs) was developed. The RGB-detector was built with 3D printing using PLA+ and reused Li-ion batteries. It is Arduino-based, which provides an easy interface between the sensor TCS3200, which reads the quadratic wave of the times corresponding to the RGB numbers, the Arduino itself, whose software translates the times into RGB values, and the touchscreen display, NX3224T028, which shows the results. This detector permits multi-sample analysis since it has a sample holder that can keep up to six µPADs simultaneously and rotate after the display's request. This work shows how the readings of the RGB indexes by the proposed RGB-detector implement the measurements' reproducibility. As a proof-of-concept, the RGB-detector application to a green array of µPADs for pH measurement coupled with chemometric analysis allowed us to achieve good results in terms of precision and agreement with the pH values measured by a classical pH-meter. [ABSTRACT FROM AUTHOR]

Abstract A novel and one-pot calcination method is applied for the fabrication of SnS nanoparticles coated by ultrathin carbon layer on carbon paper, resulting in a SnS/C-carbon paper free-standing electrode for lithium ion batteries. In this hierarchical structure, the carbon layer has dual function of buffering the volume change of SnS and anchoring SnS nanoparticles on the substrate compactly. Besides, it also can boost charge transfer kinetic in the electrode. Meanwhile, the carbon paper with three-dimensional structure allows for fully absorption of electrolyte and provides efficient transport pathways for electrons. Benefiting from these structure features, the binder-free SnS/C-carbon paper electrode exhibits excellent cyclability and delivers a reversible capacity of 696.2 mAh g−1 at a current density of 0.5 A g−1 after 200 cycles. Besides, SnS/C-carbon paper free-standing electrode achieves a reversible capacity of 562.3 mAh g−1 at a current density of 2.0 A g−1, demonstrating a promising rate ability which is significant for high power applicants. Such one-pot and novel route to synthesize SnS/C-carbon paper free-standing electrode with excellent electrochemical performance can pave the way for the development of low-cost and time-saving fabrication of free-standing anode for high-performance lithium ion batteries. Graphical abstract Image 1 Highlights • The carbon-coated SnS nanoparticles are directly assembled on carbon paper. • The composite is prepared by novel and one-pot calcination method. • Carbon layer anchor SnS on the substrate compactly and buffer the volume change. • The carbon paper provides sufficient transport pathways for electron and Li ion. • The electrode shows extended cycle life and excellent rate performance. [ABSTRACT FROM AUTHOR]

Abstract Lithium-Sulfur (Li-S) batteries are known for their high energy density and cost-effectiveness. However, the Li-S chemistry is a challenging topic due to the shuttle effect and the use of highly reactive lithium metal anode. To solve these issues, ultra-lightweight multilayered graphene coated paper separator is proposed as an interlayer. The interlayer is firstly coated on nickel foil by Chemical Vapor Deposition (CVD) method followed by transferring to the paper by fishing process. By employing this unique technique, a very light (∼8 μg/cm2) graphene coating layer is obtained which does not further imply lowering the entire energy density of the cell. As a whole, the cell with graphene coated paper exhibits 610 mAh/g discharge capacity at C/5 after 100 cycles, while the cell without interlayer exhibits much poorer performance. The improved performance is mostly associated with the interaction between graphene and polysulfide species which is proven by X-Ray Photoelectron Spectroscopy measurement as well as the excellent electronic conductivity of graphene layer which behaves as a secondary current collector resulting the cell resistance decrease. Graphical abstract Image 1 Highlights • Graphene is conformally coated on nickel foil by Chemical Vapor Deposition. • Graphene is transferred to paper in water by fishing process. • Graphene coating has one of the lowest weight (8 μg/cm2) used in Li-S batteries. • 610 mAh/g discharge capacity is gained after 100 cycles with graphene coated paper. [ABSTRACT FROM AUTHOR]

This study demonstrates the preparation of well aligned-carbon nanotube (WA-CNT) arrays onto a carbon paper substrate with a conductive carbon-black layer by the catalyst seed-impregnated chemical vapor deposition method. The prepared WA-CNT arrays were then characterized by scanning electron microscopy for different growth temperatures, standard linear velocities of feed vapors, and ferrocene-to-xylene ratios in the feed vapors. Results indicate that the optimal WA-CNT arrays of length 40–50 μm and diameter 30–40 nm were obtained at the growth temperature range of 750–800 °C, standard linear velocity of 1.40 cm s −1 , and ferrocene-to-xylene molar ratio of 1:50–1:30. These results provide new insights into the growth mechanism of CNT arrays, which involves cross-coupling of chemical reaction and mass transfer based on reaction engineering theory. The samples prepared in the study can be used as catalyst supports in air electrodes considering their three-dimensional porous structure, approximately linear channel, controllable length and diameter distribution, and excellent CNT conductivity. Electrochemical measurement indicated that the WA-CNT arrays/carbon-black layer/carbon paper substrate composites achieved relatively high discharge capacity of 2930 mAh g −1 (CNTs) at a current density of 0.05 mA cm −2 in Li–air batteries, which far exceeded other carbonaceous materials in Li–air batteries. [ABSTRACT FROM AUTHOR]

A paper-supported inorganic composite (PIC) separator is prepared by spraying Al 2 O 3 particles onto both surfaces of a commercial paper substrate. The as-prepared PIC separator shows excellent thermal stability without any shrinkage at 130 °C for 30 min, superior wettability towards the electrolyte, with a contact angle of 0°, and high ionic conductivity compared with that of the conventional polyethylene (PE) separator. The graphite|LiCoO 2 full-cells with the PIC separator exhibit good cycling and rate performance. In the nail penetration tests, the pouch cell assembled with the PIC separator shows high safety characteristics. Given the advantages of the PIC separator, it is a good potential replacement for the polyolefin separators used in high-safety lithium-ion batteries. [ABSTRACT FROM AUTHOR]

• A novel method was developed to prepare graphene-based aerogels as electrodes. • The electrode preparation process was simple with no slurry-coating procedure. • The original fascinating structure of aerogels was well retained in the electrode. • MoS 2 /graphene electrodes showed ultrahigh capacities in rechargeable batteries. In this work, we developed a drop coating-freeze drying-thermal reduction method to prepare ultrathin MoS 2 nanosheets/graphene hybrid aerogels on a carbon fiber paper substrate (MoS 2 /GS-A), which is simpler, more efficient and easier to amplify than conventional hydrothermal or chemical vapor deposition (CVD) methods. More importantly, the preparation of aerogels and electrode is completed simultaneously, which not only greatly simplifies the traditional electrode preparation but also avoids the damage of aerogel structure caused by grinding, so as to construct a long-range three-dimensional connected conductive network and porous structure at the electrode level. Benefitting from the superb electronic and ionic transport kinetics across the whole electrode, the electrode delivered an ultra large capacity of 1709 mAh g−1 at 0.2 A g−1 and remarkable rate capability of 1384 and 865 mAh g−1 at current densities of 0.6 and 1.0 A g−1 in lithium-ion batteries. Moreover, the electrode also exhibited outstanding sodium-ion storage capacity, and a stable charge capacity of 850 mAh g−1 was retained after 100 cycles under 0.1 A g−1. [ABSTRACT FROM AUTHOR]

Tin monosulfide (SnS) serves as a promising anode material in lithium-ion batteries (LIBs) due to its high theoretical capacity. However, its low rate capability and cycle stability due to poor electrical conductivity and large volume change remain urgent issues to be resolved. Here, we provide an efficient and facile strategy to achieve three-dimensional (3D) freestanding sulfur and nitrogen co-doped SnS/graphene nanocomposite (SnS/3DSNG). Benefiting from excellent electronic conductivity, improved volume flexibility, short transport length, and numerous active sites, the nanocomposite exhibits high initial discharge capacity (1030 mA h g−1 at 1 A g−1), excellent cycling stability (530 mA h g−1 at 1 A g−1 after 500 cycles) and great rate performance. The pseudo-capacitance can be improved (93.9 % at 1 mV s−1) by regulating the ratio of S and N co-doped graphene (3DSNG) and SnS. This study presents an efficient and simple method to improve the electrochemical performance of SnS-based lithium-ion batteries. [ABSTRACT FROM AUTHOR]

Wrinkled-paper-like ZnCo 2 O 4 nanoflakes were synthesized by a facile hydrothermal synthesis and a post-annealing treatment. As an anode for lithium-ion batteries, it exhibits high capacity, excellent cyclability and ultrahigh rate performance. A reversible capacity of 1138 mAh g −1 at 1 A g −1 was obtained after 500 cycles. After cycled at current densities from 0.2 to 25.6 A g −1 , the reversible capacity can recover to 1089 mAh g −1 at 0.2 A g −1 . It has been demonstrated that the wrinkled-paper-like ZnCo 2 O 4 nanoflakes are promising for application as future energy storage units. [ABSTRACT FROM AUTHOR]

One key challenge in flexible batteries lies in the development of deformable/flexible electrode with high active materials mass loading and good electronic conductivity. Herein, we report such a paper-like TiO 2 /graphene-carbon nanotube hybrid electrode by a facile vacuum filtration approach. In this electrode, titania nanoparticles with uniform size (9 nm) and carbon nanotubes are embedded into graphene sheet homogeneously, forming a peculiar 3D conducting network. This feature ensures 1) a high TiO 2 mass loading (77.3 wt %, 2.93 mg cm −2 ); 2) good electric conductivity (∼1000 S m −1 ); and 3) good flexibility. Benefiting from these, the electrode delivers a high specific capacity (214 mAh g −1 ), excellent rate capability, and up to 700 cycles stability at a high rate of 1000 mA g −1 . This fabrication strategy demonstrates great practical potential and opens up new idea for high-performance self-supported electrode design. [ABSTRACT FROM AUTHOR]

Fluoroethylene carbonate (FEC)-based electrolytes using FEC as the co-solvent (50 wt%) are investigated and compared with the electrolyte using FEC as the additive (10 wt%) for freestanding Si-carbon nanotubes (CNTs) composite paper anodes for Li-ion batteries. The ethylene carbonate (EC)-free FEC-based electrolyte is found to achieve higher specific capacity and better capacity retention in terms of long-term cycling. After 500 cycles, the capacity retention of the cell using diethyl carbonate (DEC)-FEC (1:1 w/w) is increased by 88% and 60% compared to the cells using EC-DEC-FEC (45:45:10 w/w/w) and EC-FEC (1:1 w/w), respectively. Through SEM-EDX and XPS analyses, a possible reaction route of formation of fluorinated semicarbonates and polyolefins from FEC is proposed. The inferior cell performance related to the EC-containing electrolytes is likely due to the formation of more polyolefins, which do not favor Li ion migration. [ABSTRACT FROM AUTHOR]

This paper is a product purity study of recycled Li-ion batteries with a focus on hydrometallurgical recycling processes. Firstly, a brief description of the current recycling status was presented based on the research data. Moreover, this work presented the influence of impurities such as Cu, Fe and Mg on recovered cathode materials performance. The impact of the impurities was described depending on their form (metallic or ionic) and concentration. This work also reviewed hydrometallurgical recycling processes depending on the recovered material, obtained purity and recovery methods. This purity data were obtained from both research and battery industry actors. Finally, the purity study was completed by collecting data regarding commercial battery-grade chemical compounds and active lithium cathode materials, including required purity levels and allowed impurity limitations. [ABSTRACT FROM AUTHOR]

Designing a high capacity and long cycle life MnO-based composite material for lithium ion batteries (LIBs) is still a great challenge because of the intrinsically low electrical conductivity and dramatic volume variations during lithiation/delithiation. In this paper, the MnO nanoparticles (MnO NPs) are recombined with multi-walled carbon nanotubes (MWCNTs) and reduced graphene oxide (r-GO) to rationally construct a novel MnO NPs@MWCNTs/r-GO multilayer sandwich structure via electrostatic interaction self-assembly and vacuum filtration processes. As a result, the MnO NPs are closely attracted in the conductive MWCNTs network, and the MWCNTs adsorbed on the surface of MnO NPs can be served as a soft and flexible carbon coating layer to self-adapt the huge volume expansion. For another, the r-GO between two MnO NPs@MWCNTs layers is the cause to form a free-standing paper, enhancing the transverse conductivity of the whole electrode simultaneously. These features will contribute to achieve excellent cycling stability and improved rate capability. [ABSTRACT FROM AUTHOR]

A flexible Bi 2 Se 3 /Graphene (BSG) composite paper has been prepared through a simple vacuum filtration method and a thermal reduction together. The BSG composite paper was directly used as anode electrode for lithium-ion batteries, without using any polymer binders or conduction additives. In contrast to the pure Bi 2 Se 3 , the BSG exhibits high reversible lithium ion storage capacities and superior cyclic capacity retention. It proposed that the superior lithium storage performances would be attributed to the special construction of the as-prepared BSG paper, in which the graphene can not only act as conductive network for electrodes, but also act as a frame to alleviate volume expansion or aggregation of Bi 2 Se 3 nanosheets during lithiation/delithiation. The as-prepared BSG paper shows a great potential as an anode materials for flexible Li-ion batteries. [ABSTRACT FROM AUTHOR]

The present paper uses scientometric indicators to examine the Li-ion battery research in India as reflected through Web of Science Core Collection (WoS) data of 32 years (1989-2020). India produced 2864 publications during the period but the publication activity increased manifold during the last decade. The output was scattered among 1346 institutions. However, 28 institutions produced 1% or more of the total output. One third (34.5%) of the output emerged out of international collaboration. About 71.5% of the output were in journals with impact factor >=2. The paper also identifies the aspects/direction of research through keyword analysis besides identifying preferred journals and prolific authors. [ABSTRACT FROM AUTHOR]

This work presents a novel binder-free nitrogen-doped carbon paper electrode (NCPE), which was derived from a N-rich polypyrrole (PPy)/cellulose-chopped carbon filaments (CCFs) composite, for Li–O 2 batteries. The fabrication of NCPE involved cheap raw materials ( e.g., Cladophora sp. green algae) and easy operation ( e.g., doping N by a carbonization of N-rich polymer), which is especially suitable for large-scale production. The NCPE exhibited a bird's nest microstructure, which could provide the self-standing electrode with considerable mechanic durability, fast Li + and O 2 diffusion, and enough space for the discharge product deposition. In addition, the NCPE contained N-containing function groups, which may promote the electrochemical reactions. Furthermore, binder-free architecture designs can prevent binder-involved parasitic reactions. A Li–O 2 cell with the NCPE displayed a cyclability of more than 30 cycles at a constant current density of 0.1 mA/cm 2 . The 1st discharge capacity for a cell with the NCPE reached 8040 mAh/g at a current density of 0.1 mA/cm 2 , with a cell voltage around 2.81 V. A cell with the NCPE displayed a coulombic efficiency of 81% on the 1st cycle at a current density of 0.2 mA/cm 2 . These results represent a promising progress in the development of a low-cost and versatile paper-based O 2 electrode for Li–O 2 batteries. [ABSTRACT FROM AUTHOR]

Silicon has been considered as one of the most promising anode materials for the next generation lithium-ion battery due to its high theoretical capacity, but large volume changes during the electrochemical cycling limit its commercial application. In this study, we report the synthesis of silicon carbide @ silicon core–shell nanowires on carbon paper and their application in lithium-ion batteries. The hybrid nano-structures are fabricated via a two-step chemical vapor deposition method and directly used as the working electrode without any additional binder, exhibiting high specific capacity, high coulombic efficiency and good cycling stability. After 50 cycles, the discharge capacities still remain 2837 and 1809 mAh g −1 at the rates of 0.1C and 0.5C, respectively. Furthermore, we also study the influence of the growth time of SiC NWs and the thickness of Si film on the lithium-ion batteries' performance, and propose the possible method to further improve the battery performance. [ABSTRACT FROM AUTHOR]

The Titanium dioxide–Carbon (TiO2–C) nanocomposite (NC) was fabricated by a hydrothermal method. The present work is to introduce the carbon material in Li-ion batteries for optimizing it to better electrical performance and to enhance its property. Lithium-ion battery is prepared by using titanium tetrachloride and commercial filter paper as the carbon source. The battery performance is highly influenced by the weight ratio of TiO2–C in the sample. For this work, a new method is adapted to tune the weight percentage of TiO2 and carbon in the composite while elevating calcination temperatures. Optimized battery performance of TiO2 nanocomposite was analyzed by 150 cycles at various calcination temperatures viz., 400 °C, 450 °C, and 500 °C, the charge capacities have existed at 301 mAh g−1, 352 mAh g−1, and 402 mAh g−1 at a current density of 100 mA g−1. The first discharge capacity was achieved for three prepared samples (400 °C, 450 °C, and 500 °C) to be 1068 mAh g−1, 1271 mAh g−1, and 1467 mAh g−1 at a current density of 100 mA g−1. The prepared electrode shows high charge and discharge capacity during long cycling. [ABSTRACT FROM AUTHOR]

Mg/Al-hydrotalcite (HDT)-dispersed paper-structured catalyst (PSC) was prepared by a simple paper-making process. The PSC exhibited excellent catalytic activity for the steam reforming of model biodiesel fuel (BDF), pure oleic acid methyl ester (oleic-FAME, C 19 H 36 O 2 ) which is a mono-unsaturated component of practical BDFs. The PSC exhibited fuel conversion comparable to a pelletized catalyst material, here, conventional Ni–zirconia cermet anode for solid oxide fuel cell (SOFC) with less than one-hundredth Ni weight. Performance of electrolyte-supported cell connected with the PSC was evaluated in the feed of oleic-FAME, and stable operation was achieved. After 60 h test, coking was not observed in both SOFC anode and PSC. [ABSTRACT FROM AUTHOR]

With the widespread application of energy storage stations, BMS has become an important subsystem in modern power systems, leading to an increasing demand for improving the accuracy of SOC prediction in lithium-ion battery energy storage systems. Currently, common methods for predicting battery SOC include the Ampere-hour integration method, open circuit voltage method, and model-based prediction techniques. However, these methods often have limitations such as single-variable research, complex model construction, and inability to capture real-time changes in SOC. In this paper, a novel prediction method based on the KF-SA-Transformer model is proposed by combining model-based prediction techniques with data-driven methods. By using temperature, voltage, and current as inputs, the limitations of single-variable studies in the Ampere-hour integration method and open circuit voltage method are overcome. The Transformer model can overcome the complex modeling process in model-based prediction techniques by implementing a non-linear mapping between inputs and SOC. The presence of the Kalman filter can eliminate noise and improve data accuracy. Additionally, a sparse autoencoder mechanism is integrated to optimize the position encoding embedding of input vectors, further improving the prediction process. To verify the effectiveness of the algorithm in predicting battery SOC, an open-source lithium- ion battery dataset was used as a case study in this paper. The results show that the proposed KF-SA-Transformer model has superiority in improving the accuracy and reliability of battery SOC prediction, playing an important role in the stability of the grid and efficient energy allocation. [ABSTRACT FROM AUTHOR]

A 3-dimensional carbonized multi-walled carbon nanotube (MWCNT) paper was used as the host of nano-tin oxide (SnO2) for lithium-ion batteries (LIBs). The cellulose fibers were fully mixed with MWCNTs in water. Then, the paper was obtained via vacuum filtration. Carbonization was carried out in a vacuum furnace at 1460°C. SnO2 slurry was coated on the carbonized MWCNT paper (CMP). Scanning electron microscopy (SEM) was utilized to observe the anode electrode. The images of SEM indicated that the nano-SnO2 was embedded into the holes of the porous CMP collector. This contributed the increase of contact interface area of the nano-SnO2 and the collector and the significantly reduced interface resistance. Electrochemical tests showed that the initial discharge capacity reached 1745 mAh g−1 with a coulumbic efficiency (CE) of 70.39% at a current density of 50 mA g−1. The composite electrode still maintained a reversible capacity of 753 mAh g−1 with a CE of 98% at a current density of 200 mA g−1 after 100 cycles. These marvelous composite electrodes exhibited a promising future for the next generation of LIBs. [ABSTRACT FROM AUTHOR]

Highlights: [•] Graphene was covalently modified to have polycaprolactone brushes on the surface. [•] Functionalized graphene paper exhibited super-toughness and high flexibility. [•] Lithium ion battery anode fabricated from the paper showed excellent capacity. [Copyright &y& Elsevier]

A smooth, free-standing and flexible graphene oxide paper was produced using a vacuum filtration technique. This graphene oxide paper was characterized by scanning electron microscopy, X-ray diffraction and Raman spectroscopy techniques. The charge–discharge characteristics of the graphene oxide paper have been investigated from 1 V to 4.5 V at a constant 0.01 mA cm −2 with an ECC–Air test cell. The electrochemical impedance of the graphene oxide paper has been measured to investigate the difference in the resistance of the cell before and after an electrochemical cycling test. The Li–air cell with a graphene oxide flexible paper cathode exhibited a 612 mAh g −1 discharge capacity and a 555 mAh g −1 charge capacity after 10 cycles. This study demonstrated that graphene oxide paper might be a good alternative cathode material for Li–O 2 batteries in the future. [ABSTRACT FROM AUTHOR]

Abstract: We have designed the air electrode for rechargeable Li–O2 batteries by adapting conventional current collectors-carbon papers (CPs), as freestanding substrates. The MnO2@CP electrodes are prepared by simply floating CPs on KMnO4 solution at room temperature. CPs act as the reducing agents as well as the freestanding substrates. Birnessite-type MnO2 nanosheets are observed to in situ grow vertically from the surface of CPs, thus building 3D porous architecture. The nanosheets are uniformly distributed and interconnected each other, which contributes to an improved electrical connection among the MnO2 catalyst and CPs. The cycling tests using the electrode as the cathode in rechargeable Li–O2 batteries exhibit high reversibility and superior cycling stability, over 90 cycles with a capacity of more than 1000 mA h (g MnO2)−1 and a high coulombic efficiency of around 100% in the voltage rang of 2.2–4.4 V. [Copyright &y& Elsevier]

[Display omitted] • A novel aramid nanofibers reinforced cellulose membrane was developed as an advanced LIB separator. • The large pores and insufficient thermomechanical properties of cellulose separator was improved. • The influence of aramid nanofibers on the comprehensive performance of cellulose composite separator was presented. • The composite separator achieved well balance between high safety and excellent electrochemical performance. Commercial polyolefin separators suffer from poor electrolyte wettability and low thermal stability, which give rise to unsatisfied electrochemical performance and severe safety hazards for lithium-ion batteries (LIBs). Herein, a novel paper-based composite separator composed of electrolyte-affinitive cellulose fibers (CFs) and thermally stable aramid nanofibers (ANFs) was successfully fabricated through the traditional papermaking method. The ANFs as a functional nanofiller played crucial roles in improving the defects of pure CF separator including large-sized pores, low mechanical strength and high flammability. Specifically, the CF/ANF composite separator with 20 wt% ANFs (CF/ANF-20) possessed narrow micropores, satisfied tensile strength (33 MPa), excellent thermal resistance (without dimensional shrinkage up to 200 °C) and flame retardancy, which greatly enhanced the safe operation of battery. Moreover, inheriting from the highly porous structure and exceptional electrolyte affinity of CF separator, the CF/ANF-20 composite separator exhibited appropriate porosity and superior electrolyte wettability, which brought about a high electrolyte uptake (157%), thus endowing it with better ionic conductivity (0.75 mS cm−1) and lower interfacial resistance compared to commercial polypropylene separator. Accordingly, the LiFePO4/Li half cells using CF/ANF-20 separator delivered outstanding rate capability and stable cycling performance. All results indicate that the CF/ANF-20 separator shown great balance between the electrochemical performance and safety is an intriguing candidate for advanced LIBs. [ABSTRACT FROM AUTHOR]

The state of health (SOH) of lithium-ion batteries is an important indicator for evaluating the degradation of battery performance, which is crucial in battery management systems. With the development of science and technology, data-driven models used to predict SOH are widely used, while data-driven models generally suffer from a narrow estimation range, long prediction time, and poor accuracy. Therefore, this paper introduces the extreme learning machine model with a single hidden layer that incorporates hybrid kernel functions, which overcomes the mapping defect problem of single kernel extreme learning machine and extreme learning machine by the introduction of hybrid kernel functions and improves the range and speed of data-driven models for SOH prediction. In addition, to automatically find the optimal parameters of the kernel extreme learning machine to improve the accuracy, the dung beetle algorithm with strong parameter finding ability is used to optimize the model in this paper. Meanwhile, based on the algorithm, we introduced the optimal Latin hypercube idea and weight factor for initializing the population and regulating the position update, respectively, which effectively improved the convergence and parameter-seeking ability of the algorithm to improve the accuracy of the model. The experiments verified the reasonableness and effectiveness of the proposed model, in which the optimal results of root mean square error, average absolute percentage error, and coefficient of determination of the proposed model on the battery dataset were 0.177%, 0.046%, and 99.76%, respectively, which reflected the high-precision prediction ability and strong robustness. [ABSTRACT FROM AUTHOR]

Though lithium-ion batteries are extensively applied in electric vehicles as a power source due to their excellent advantages in recent years, the security risk has inarguably always existed. The state of health (SOH) of lithium-ion batteries is one of the most important indicators related to security, the prediction of SOH is paid close attention spontaneously. To improve the prediction accuracy of SOH, this paper constructs an SOH prediction model based on a multi-kernel relevance vector machine and error compensation (EC-MKRVM). The provided model comprises a pre-estimation model and an error compensation model, both of which use the multi-kernel relevance vector machine (MKRVM) algorithm. The pre-estimation model takes the feature factors extracted in the charging segment as the input variable and the SOH pre-estimation value as the output. The error compensation model takes the pre-estimation error sequence as the input variable and the SOH prediction error as the output. Finally, the SOH prediction error is used to compensate for the SOH pre-estimation value of the pre-estimation model, and the final SOH prediction value is obtained. To verify the effectiveness and advancement of the model, the CACLE dataset is used for comparative experimental analysis. The results show that the proposed prediction model in this paper has higher prediction accuracy. [ABSTRACT FROM AUTHOR]

Two dimensional nanosheets, such as graphene and metal disulfides, have attracted a great deal of attention as anode materials for lithium-ion batteries, owing to their unique capability for lithium-ion storage. In this work, we integrate graphene and MoS 2 nanosheets into a free standing film form using a simple vacuum filtration method. As-prepared composite film could be readily employed as a binder- and carbon-free anode for lithium-ion batteries, removing the polymeric binders and conductive carbon additives that are required for the preparation of conventional electrodes. In addition, the interconnected structure of graphene and MoS 2 sheets provide a good electrical conductivity to the entire film electrode. When tested electrochemical performance as an anode for lithium-ion batteries, the composite film electrode exhibits superior performance compared to the exfoliated MoS 2 electrode, such as 65.8% capacity retention at a high current rate of 1000 mA g −1 and 91.1% capacity retention after 100 cycles. [ABSTRACT FROM AUTHOR]

An introduction to a special issue of the journal is presented in which the editor discusses various reports within the issue on topics including a study on lithium ion batteries, a study on semi-interpenetrating networks based on polymerized Ionic Liquids (ILs) and silica synthesis using ILs.

The article announces the recipients of Energies Best Paper Awards for 2015 fore several research papers on topics including carbon emissions in the U.S., evaluation of lithium-ion battery equivalent circuit models and AC power routing system.

The accurate estimation of lithium-ion battery state of charge (SOC) is the key to ensuring the safe operation of energy storage power plants, which can prevent overcharging or over-discharging of batteries, thus extending the overall service life of energy storage power plants. In this paper, we propose a robust and efficient combined SOC estimation method, GRU-ASG, which combines the gated recurrent unit (GRU) neural network and the adaptive Savitzky-Golay filter (ASG). Firstly, the "many-to-one" structure GRU is used to establish the mapping model between the battery-measured variables (voltage, current, temperature) and SOC, and achieve the SOC initial estimation. Then, the output SOC of the GRU network is smoothed online using the Spielman coefficient–based ASG filtering algorithm proposed in this paper to reduce the fluctuation of SOC. Finally, the accurate and stable estimated SOC is obtained. This paper uses six different operating condition datasets collected from an energy storage plant during the discharge process and uses four of them as training datasets and the remaining two as test datasets. The results show that the proposed method can select the optimal window length online adaptively to smooth the initial estimate of SOC. Moreover, the estimation accuracy of the proposed method is the highest compared to the single GRU network and the GRU network with a combination of other filtering algorithms. In particular, the mean square error (MSE) is less than 0.15% and the mean absolute error (MAE) is less than 3% for the two test sets. [ABSTRACT FROM AUTHOR]

With the rapid development of lithium-ion batteries, the electrode becomes more and more miniaturized. It is necessary to analyze the stress and axial force in the nanowire electrode. The main work of this paper is to analyze the stresses and buckling in homogeneous material nanowire electrodes and two kinds of composition-gradient (positive gradient and negative gradient) material nanowire electrodes of lithium-ion batteries. Comparing the diffusion-induced stresses (DISs) and buckling in three electrodes, we analyze the advantage of composition-gradient material electrodes on DISs and axial forces. The finite deformation theory and the stress-induced diffusion hypothesis are adopted to establish the constitutive equations, and the nonlinear influence of large deformation is considered. We conclude that ratios of length to radius and constraint conditions have great influence on the buckling of nanowire electrodes. The composition-gradient materials can reduce the stress and prevent the electrode from buckling. Under the same constraint condition, the positive gradient with smaller ratio of length to radius and smaller diffusion flux can delay buckling. When the ratio of length to radius are larger and the diffusion flux is larger, the negative gradient can delay buckling. The results can provide a theoretical guidance on the way of charging operation and the design of electrodes. [ABSTRACT FROM AUTHOR]

This study presents a review of how the end-of-life (EOL) stage is modelled in life cycle assessment (LCA) studies of lithium-ion batteries (LIBs). Twenty-five peer-reviewed journal and conference papers that consider the whole LIB life cycle and describe their EOL modelling approach sufficiently were analyzed. The studies were categorized based on two archetypal EOL modelling approaches in LCA: The cutoff (no material recovery, possibly secondary material input) and EOL recycling (material recovery, only primary material input) approaches. It was found that 19 of the studies followed the EOL recycling approach and 6 the cutoff approach. In addition, almost a third of the studies deviated from the expected setup of the two methods by including both material recovery and secondary material input. Such hybrid approaches may lead to double counting of recycling benefits by both including secondary input (as in the cutoff approach) and substituting primary materials (as in the EOL recycling approach). If the archetypal EOL modelling approaches are not followed, it is imperative that the modelling choices are well-documented and motivated to avoid double counting that leads to over- or underestimations of the environmental impacts of LIBs. Also, 21 studies model hydrometallurgical treatment, and 17 completely omit waste collection. [ABSTRACT FROM AUTHOR]