Effect of varying carbon microstructures on the ion storage behavior of dual carbon lithium-ion capacitor

Dual carbon lithium-ion capacitors (LICs) are the next-generation hybrid energy storage devices that aim towards energy-power balanced applications. Thus, tuning the properties of the carbon electrode materials is a crucial step toward optimizing the device's performance. Herein, the effect of change in the microstructure of the carbon electrodes on the ion storage capacity and their consequent energy-power manifestation is investigated. The optimized carbonaceous anode calcined at 700 ⁰C delivers 290 mAh g−1 capacity after 1000 cycles at 1 A g−1. This superiority in performance is attributed to the formation of micron-size channels and mesopores for better ion transport and storage. In contrast, the activated carbon cathode delivers a capacitance of 118 F g−1 and retains 76% at the end of 5000 cycles. The LIC full cell with these electrode materials provides maximum energy of 120 Wh kg−1, a maximum power density of 20.7 kW kg−1 and cycles till 9000 cycles with ∼67% capacitance retention. The mechanistic control over the deliverable ion storage capacity is also analyzed for the LIC full cell. Furthermore, the lighting demonstration, self-discharge studies, leakage current, and electrochemical impedance are recorded to elucidate the practical feasibility and performance degradation mechanism of the coin-cell device

Synthesis, crystal structure, optical, thermoelectric, and electrochemical studies of Ba2Cu2.1(1)Ag1.9(1)Se5

We present the synthesis and characterization of single crystals and polycrystalline samples of Ba2Cu2.1(1)Ag1.9(1)Se5. A single-crystal X-ray diffraction study confirms its monoclinic structure (space group: C2/m) with lattice parameters of a = 16.0342(15) Å, b = 4.4162(4) Å, c = 9.1279(9) Å, β = 124.005(2)°, V = 535.82(9) Å3, and Z = 2. The structure of Ba2Cu2.1(1)Ag1.9(1)Se5 consists of polyanionic [∞2Cu2.1(1)Ag1.9(1)Se5]4− layers. The negative charges on these layers are counterbalanced by the filling of Ba2+ cations in the structure. The Ag and Cu atoms are statistically disordered at the same sites. The Ag/Cu atoms are bonded with four Se atoms in a distorted tetrahedral fashion. The structure also contains linear Se34− units with intermediate Se⋯Se interaction of 2.7734(14) Å. The Ba2Cu2.1(1)Ag1.9(1)Se5 can be charge-balanced as (Ba2+)2(Cu+)2.1(Ag+)1.9(Se2−)2(Se34−)1. The optical absorption study performed on a polycrystalline sample with a loaded composition of Ba2Cu2.1Ag1.9Se5 reveals a direct bandgap of 1.0(2) eV, and the indirect bandgap was found to be below 0.5 eV. The resistivity study also confirmed the semiconducting nature of the sample. The thermoelectric properties, including thermal conductivity and Seebeck coefficient, have been studied as a function of temperature. The polycrystalline Ba2Cu2.1Ag1.9Se5 has a very low thermal conductivity value of 0.46 W/mK at 673 K. The positive sign of the Seebeck coefficient values indicates the polycrystalline Ba2Cu2.1Ag1.9Se5 is a p-type semiconductor with holes as the majority of charge carriers. Further, the charge storage behavior of the material was investigated for supercapacitor application. The material delivers 76 F g−1 at 0.5 A g−1 current density in 1 M KOH electrolyte and is stable for 10,000 cycles retaining 85% capacitance

A Novel and Sustainable Approach to Enhance the Li-Ion Storage Capability of Recycled Graphite Anode from Spent Lithium-Ion Batteries

The ubiquitous manufacturing of lithium-ion batteries (LIBs) due to high consumer demand produces inevitable e-waste that imposes severe environmental and resource sustainability challenges. In this work, the charge storage capability and Li-ion kinetics of the recovered water-leached graphite (WG) anode from spent LIBs are enhanced by using an optimized amount of recycled graphene nanoflakes (GNFs) as an additive. The WG@GNF anode exhibits an initial discharge capacity of 400 mAh g-1 at 0.5C with 88.5% capacity retention over 300 cycles. Besides, it delivers an average discharge capacity of 320 mAh g-1 at 500 mA g-1 over 1000 cycles, which is 1.5-2 times higher than that of WG. The sharp increase in electrochemical performance is due to the synergistic effects of Li-ion intercalation into the graphite layers and Li-ion adsorption into the surface functionalities of GNF. Density functional theory calculations reveal the role of functionalization behind the superior voltage profile of WG@GNF. Besides, the unique morphology of spherical graphite particles trapping into graphene nanoflakes provides mechanical stability over long-term cycling. This work explains an efficient strategy to upgrade the electrochemical compatibility of recovered graphite anode from spent LIBs toward next-generation high-energy-density LIBs

A review on spent lithium-ion battery recycling: from collection to black mass recovery

The advent of lithium-ion battery technology in portable electronic devices and electric vehicle applications results in the generation of millions of hazardous e-wastes that are detrimental to the ecosystem. A proper closed-loop recycling protocol reduces the environmental burden and strengthens a country with resource sustainability, circular economy, and the provision of raw materials. However, to date, only 3% of spent LIBs have been recycled. The recycling efficiency can be further increased upon strong policy incentives by the government and legislative pressure on the collection rate. This review sheds light on the pretreatment process of end-of-life batteries that includes storage, diagnosis, sorting, various cell discharge methods (e.g., liquid medium, cryogenic and thermal conditioning, and inert atmosphere processing), mechanical dismantling (crushing, sieving, sequential, and automated segregation), and black mass recovery (thermally and solvent leaching). The advantage of the stagewise physical separation and practical challenges are analyzed in detail. Disassembling the battery module pack at the cell level with the improved technology of processing spent batteries and implementing artificial intelligence-based automated segregation is worth it for high-grade material recovery for battery applications. Herein, we outline an industry-viable mechanochemical separation process of electrode materials in a profitable and ecofriendly way to mitigate the energy demand in the near future

Nanostructured Silicon–Carbon 3D Electrode Architectures for High-Performance Lithium-Ion Batteries

Silicon is an attractive anode material for lithium-ion batteries. However, silicon anodes have the issue of volume change, which causes pulverization and subsequently rapid capacity fade. Herein, we report organic binder and conducting diluent-free silicon–carbon 3D electrodes as anodes for lithium-ion batteries, where we replace the conventional copper (Cu) foil current collector with highly conductive carbon fibers (CFs) of 5–10 μm in diameter. We demonstrate here the petroleum pitch (P-pitch) which adequately coat between the CFs and Si-nanoparticles (NPs) between 700 and 1000 °C under argon atmosphere and forms uniform continuous layer of 6–14 nm thick coating along the exterior surfaces of Si-NPs and 3D CFs. The electrodes fabricate at 1000 °C deliver capacities in excess of 2000 mA h g–1 at C/10 and about 1000 mA h g–1 at 5 C rate for 250 cycles in half-cell configuration. Synergistic effect of carbon coating and 3D CF electrode architecture at 1000 °C improve the efficiency of the Si–C composite during long cycling. Full cells using Si–carbon composite electrode and Li1.2Ni0.15Mn0.55Co0.1O2-based cathode show high open-circuit voltage of >4 V and energy density of >500 W h kg–1. Replacement of organic binder and copper current collector by high-temperature binder P-pitch and CFs further enhances energy density per unit area of the electrode. It is believed that the study will open a new realm of possibility for the development of Li-ion cell having almost double the energy density of currently available Li-ion batteries that is suitable for electric vehicles

Bio‐waste derived carbon nano‐onions as an efficient electrode material for symmetric and lead‐carbon hybrid ultracapacitors

Carbon and metal oxide nanocomposites have been extensively studied as electrode materials to develop energy and power-dense supercapacitors in recent years. Nevertheless, nano carbons with improved porosity and functional moieties are the most eco-friendly and cost-effective supercapacitor materials. In this work, carbon nano-onions (CNOs) synthesized by a single-step flame soot collection method, subsequently calcined at 600°C in an inert environment (CNO-600), are used as electrode material for the supercapacitors. CNO-600 s have a layer-by-layer nano onion structure with a ~25 nm particle size and a Brunauer–Emmett–Teller surface area of 147 m2 g−1. CNO-600 delivers 266 and 186 F g−1 of capacitance at 0.5 A g−1 for half cells and symmetric ultracapacitors, respectively. Ultracapacitors show capacitance retention of 91% with 20 000 GCD cycles in 1 M H2SO4 electrolyte. The stable capacitance of CNO-600 is due to easy intercalation/de-intercalation of electrolyte ions and electrons in the layer-by-layer structure of CNOs, contributing to pseudocapacitive charge storage with electric double layer capacitor behavior. The lead-carbon hybrid ultracapacitor fabricated using CNO-600 as anode material and PbO2 as cathode delivers a specific capacitance of 515 F g−1 at 1 A g−1 in 4.5 M H2SO4 electrolyte in the voltage range of 2.3 and 0.6 V. The substantial improvement of charge storage in CNO-based symmetric and lead-carbon hybrid system, demonstrate an excellent opportunity for the development of high-performance supercapacitors. © 2022 John Wiley & Sons Ltd

Nitrogen phosphorous derived carbons from Peltophorum pterocarpum leaves as anodes for lead–carbon hybrid ultracapacitors

Lead–carbon hybrid ultra-capacitors are emerging as an alternative to a lead-acid battery, owing to the absence of sulfation, thereby enhancing cycle life and C rate performances. In this work, Nitrogen and Phosphorous derived carbons are synthesized from the Peltophorum pterocarpum leaves by treating with phosphoric acid followed by carbonization at 550 °C for 3 hrs. These carbons contain about 3.76% of Nitrogen and 1.26% of Phosphorous and have a BET surface area of 443 m2 g−1. Specific capacitances of 1032 F g−1 and 640 F g−1 at current densities of 1 A g−1 and 10 A g−1, respectively in 4.5 M. sulfuric acid are achieved for these carbon-based electrodes. The hybrid ultra-capacitor fabricated by using PbO2 positive electrode and Nitrogen and Phosphorous derived carbons coated on to graphite sheet as a negative electrode shows cycling stability with capacitance retention of >95% for about 15,000 cycles at an applied current density of 5 A g−1. The pseudocapacitive nature of as-synthesized carbon exhibits significant improvement in electrochemical performance in lead–carbon ultra-capacitors

MoO3@ZnO Nanocomposite as an Efficient Anode Material for Supercapacitors: A Cost Effective Synthesis Approach

The high pseudocapacitance of metal oxides makes them a very promising electrode material for supercapacitors. In this work, we report a MoO3-ZnO composite as an efficient electrode material for supercapacitors. The MoO3-ZnO composite materials were synthesized by the facile solid-state impregnation-calcination method at 350 °C. The MoO3-ZnO composite shows a specific capacitance of 280 F g-1 at 1 A g-1 current density in the potential range between 0 and -1.3 V in 1 M Na2SO4. The composite material shows a power density of 650 W kg-1 at an energy density of 65 Wh kg-1 and is stable over 10 000 cycles at 5 A g-1 with 98% capacitance retention. The improved capacitive behavior of the MoO3-ZnO composite electrode is due to the redox behavior of MoO3, and the porous nature of ZnO, which facilitates the electrolyte ions interaction into the composite frameworks. The improved anodic potential charge storage nature and overall electrochemical performance depict that the MoO3-ZnO composite is a suitable electrode material for supercapacitors. © 2021 American Chemical Society

Effect of nitrogen on grain boundary character distribution in 316 stainless steel

Influence of nitrogen content and percentage of prior rolling deformation on evolution of grain boundary character distribution in 316L(N) stainless steel, during grain boundary engineering type thermo-mechanical processing, have been studied in the present work. 10% rolling deformation followed by annealing produces highest fraction of low energy Σ3 boundaries and high fraction of low energy grain boundary network in high nitrogen SS, leading to improved corrosion resistance

Pitch-Derived Soft-Carbon-Wrapped NaVPO4F Composite as a Potential Cathode Material for Sodium-Ion Batteries

Sodium vanadium fluorophosphate (NaVPO4F) is a potential electrode material for sodium-ion batteries due to its stable structural framework with a reasonable theoretical capacity of 143 mAh g-1. However, its poor electronic conductivity limits its C-rate performance and cycle stability. To solve the problem associated with poor electronic conductivity, in this work, pitch-derived soft-carbon-wrapped NaVPO4F particles with an interconnected carbon matrix is proposed. Transmission electron microscopy (TEM) and Raman studies suggest that the interlayer spacing of the soft carbon layer is around 0.47 nm, which facilitates faster kinetics upon cycling. The presence of 15% soft carbon in the composite samples results in higher Na-ion diffusion coefficient values, stable cycling, and C-rate performances. The composite cathode delivers an initial reversible capacity of 109 mAh g-1 with 95% capacity retention at 0.1C for 300 cycles. Besides, 77% capacity retention is observed after 1000 cycles at a 0.5C rate. Such a remarkable electrochemical performance is attributed to the appropriate amount of soft carbon wrapped onto NaVPO4F and the interconnected carbon matrix, which provides continuous electronic conduction, improved structural integrity, and faster kinetics of NaVPO4F particles. Finally, practical sodium-ion full cells using the NaVPO4F composite cathode and the pretreated hard carbon anode are realized. The cells show an operating voltage of 3.3 V with a capacity retention of ∼87% at the end of the 50th cycle at 30 mA g-1. This suggests that the NaVPO4F-based composite electrode materials are robust cathodes and can be potentially implemented in sodium-ion batteries