Fast Charge Rates Research Articles

Graphene supported double-layer carbon encapsulated silicon for high-performance lithium-ion battery anode materials

Carbon coating has been an effective procedure to tackle the severe structural degradation and poor conductivity during cycling of silicon-based anodes in lithium-ion batteries (LIBs). However, the traditional coated carbon usually is tight and thus limit the fast-charging rate and high specific capacity. Herein, through in-situ formation of metal-organic frameworks on the surface, silicon particles were firstly coated by an inside carbon layer. Followed by a solvothermal reaction with the mixture of sucrose and graphene oxide, the second carbon layer outside the silicon particles was deposited, and simultaneously a highly conductive graphene network was formed. After a high temperature pyrolysis process, a graphene matrix supported silicon material with inward multi-channel carbon and outward tight activated carbon was prepared. This unique core/double-layer carbon structure, combined with the highly conductive graphene frameworks, render the material to demonstrate excellent electrochemical performance as anode materials for LIBs in terms of both lithium storage capacity and cycling stability. Thus, the electrode materials deliver a high specific capacity of 1528.1 mA h g−1 at the current density of 0.1 A g−1 and rate capacity retention of 45.5% at 1 A g−1 to 0.1 A g−1. Simultaneously, a highly stable reversible capacity of 1182 mAh g−1 with 89.5% retention over 240 cycles at a current density of 0.2 A g−1 and 484 mAh g−1 with 76.8% retention after 450 cycles at 1.0 A g−1 were obtained. This work can offer an alternative approach for high-energy and low-cost silicon-based anodes for LIBs.

Resolving Current-Dependent Regimes of Electroplating Mechanisms for Fast Charging Lithium Metal Anodes.

Poor fast-charge capabilities limit the usage of rechargeable Li metal anodes. Understanding the connection between charging rate, electroplating mechanism, and Li morphology could enable fast-charging solutions. Here, we develop a combined electroanalytical and nanoscale characterization approach to resolve the current-dependent regimes of Li plating mechanisms and morphology. Measurement of Li+ transport through the solid electrolyte interphase (SEI) shows that low currents induce plating at buried Li||SEI interfaces, but high currents initiate SEI-breakdown and plating at fresh Li||electrolyte interfaces. The latter pathway can induce uniform growth of {110}-faceted Li at extremely high currents, suggesting ion-transport limitations alone are insufficient to predict Li morphology. At battery relevant fast-charging rates, SEI-breakdown above a critical current density produces detrimental morphology and poor cyclability. Thus, prevention of both SEI-breakdown and slow ion-transport in the electrolyte is essential. This mechanistic insight can inform further electrolyte engineering and customization of fast-charging protocols for Li metal batteries.

Rapid Joule Heating Method Applied to Solid State Electrolyte Materials

Designing a solid-state battery is a balancing act. Fast charging rates and high capacity are preferable, but safety and long battery lifetimes must also be preserved. When making a solid-state electrolyte, amorphous materials with greater lithium content are ideal—they have greater conductivity than their lower-lithium-content counterparts. In addition to high lithium content, recent studies have focused on eliminating grain boundaries in solid state electrolytes. Eliminating grain boundaries allows for safer charging and discharging by reducing the chances of dendrite formation and subsequent shorting. Through experiments, we tried to reconcile amorphous character and relatively higher lithium content to produce a mechanically robust, conductive electrolyte material that lasts over many cycles. We first coarsened Li3BO3 powder in a tube furnace, then pelletized the powder at 253,411 bar via hydraulic press. The rapid joule heating method involves two carbon papers connected in parallel with a DC power supply. Using this configuration, we had access to rapid quenching rates that typically require expensive technology. Resistance from the carbon paper resulted in a rapid temperature increase proportional to the applied current so the carbon paper acted as a heating element. The Li3BO3 pellet was inserted between the two papers where it heated to its melting temperature (760-880°C) within 20 sec. We hypothesized that shorter ramping and cooling times introduced by rapid joule heating would promote amorphous character in Li3BO3, compared to samples prepared in a tube furnace with longer heating and cooling times. Full width at half maximum values calculated from X-ray diffraction results for each sample suggest the samples prepared using rapid joule heating formed smaller crystalline domains than those manufactured in the tube furnace. Scanning electron microscopy images taken at 5.0k magnification confirm this calculation. Large grains can be seen in the traditionally heated sample whereas no grains are observable in the rapid joule heated sample. Smaller crystalline domains emphasize the effects of rapid cooling and encourage future studies in escalating heating and cooling rates to produce amorphous or partially amorphous electrolytes.

Printed Graphite Electrodes for Fast Charging Lithium-Ion Batteries

Fast charging capability has become one of the key features of lithium-ion batteries (LIBs) to facilitate the rapid growth of the electric vehicle (EV) market. However, charging thick electrodes in conventional EV batteries at high current densities always leads to adverse battery performance and safety issues. To address these challenges, thick graphite electrodes with patterned porous architecture were developed through a facile printing process. With selected graphite and developed formula, an appropriate graphite ink was printed onto the copper foil through the screen printing with designed patterned pore channels. The porous structure including pore diameter and pore-to-pore distance was controlled via adjusting the designed patterns on the screens. The presence of porous structure was confirmed through microscopic images. The printed graphite electrodes exhibited superior electrochemical behaviors over traditional electrodes in terms of rate capability and cycle life. It is believed that the improved battery performance is associated with the improved Li-ion transport arising from the patterned porous structure in printed electrodes. Results from the electrochemical impedance spectroscopy (EIS) indicate that, compared with traditional electrodes without patterned pores, printed electrodes have significantly reduced tortuosity. The post-mortem analysis of cycled cells demonstrates that the printed electrodes have the capability to suppress the Li plating related to fast charging rates. Combining with the advantages of low cost and high throughput, the printed electrode with patterned pores, thus, has the potential of replacing conventional electrodes in commercial LIBs to realize the fast-charging application. Keywords: Graphite, Printing, Fast charging, Li-Ion Batteries

Development of an Adequate Formation Protocol for a Non-Aqueous Potassium-Ion Hybrid Supercapacitor (KIC) through the Study of the Cell Swelling Phenomenon

Hybrid supercapacitors have been developed in the pursuit of increasing the energy density of conventional supercapacitors without affecting the power density or the lifespan. Potassium-ion hybrid supercapacitors (KIC) consist of an activated carbon capacitor-type positive electrode and a graphitic battery-type negative one working in an electrolyte based on potassium salt. Overcoming the inherent potassium problems (irreversible capacity, extensive volume expansion, dendrites formation), the non-reproducibility of the results was a major obstacle to the development of this KIC technology. To remedy this, the development of an adequate formation protocol was necessary. However, this revealed a cell-swelling phenomenon, a well-known issue whether for supercapacitors or Li-ion batteries. This phenomenon in the case of the KIC technology has been investigated through constant voltage (CV) tests and volume measurements. The responsible phenomena seem to be the solid electrolyte interphase (SEI) formation at the negative electrode during the first use of the system and the perpetual decomposition of the electrolyte solvent at high voltage. Thanks to these results, a proper formation protocol for KICs, which offers good energy density (14 Wh·kgelectrochemical core−1) with an excellent stability at fast charging rate, was developed.

Next-Generation Aviation Li-Ion Battery Technologies—Enabling Electrified Aircraft

Recent advances in electrode materials, manufacturing processes, and safety features are enabling Li-ion battery (LIB) designs to better support energy storage needs for the emerging all-electric aviation market. Increases in cell specific energy, improved fast charge and discharge rate capability, and extended cycle-life are required for the next-generation aviation platforms that consist of more-electric, hybrid, and all-electric aircraft designed to reduce generated flight noise and carbon emissions. The success of these emerging Advanced Air Mobility (AAM) markets is highly dependent upon implementing a safe and reliable energy storage system compliant with aircraft system requirements. This work discusses state-of-the-art (SOA) and emerging LIB technology readiness to meet the derived marketplace performance and imposed regulatory requirements for all-electric aircraft. A special focus on advanced LIB safety design guidelines intended to meet the intent of the FAA DO-311A minimum operational performance standard for rechargeable lithium batteries and battery systems installed on aircraft is emphasized.

Study on Li-ion battery fast charging strategies: Review, challenges and proposed charging framework

The long charging time of Li-ion batteries in comparison to ICEV (Internal Combustion Engine Vehicle) refuelling time is a barrier to the adoption of Li-ion-based EV. The electric vehicle industry believes that increasing the current rate (C-rate) will reduce charging time, but this increases the cell degradation rate. As a result, the need of the hour is to develop a health-aware battery fast charging strategy. Numerous research was conducted to develop an optimal charging algorithm, but the high complexity of the algorithms attracted fewer industries to adopt these strategies. This paper reviews twenty-six charging strategies that have a low computational burden and easy adaptability. The critical research direction facilitates understanding the limitations and provides a solution for the strategical industrial adaptability. The keys have been investigated further, and steps for developing a comprehensive charging framework have been devised. The proposed framework helps in charging management system development using a graphical user interface-based fast-charging controller. This controller aims to provide an industry-ready hybrid fast charging strategy adaptation. The fast charging rate, low battery degradation, and low complexity will facilitate faster industrial adaptation and encourage consumers to switch to EVs.

An activity-based travel and charging behavior model for simulating battery electric vehicle charging demand

The expansion of the battery electric vehicle (BEV) market requires considerable changes in the supply of electricity to fulfill the charging demand. To this end, understanding the spatio-temporal distribution of BEV charging demand at a micro level is crucial for optimal electric vehicle supply equipment (EVSE) planning and electricity load management. This research proposes an integrated activity-based BEV charging demand simulation model, which considers both realistic travel and charging behaviors and provides high-resolution spatio-temporal demand in real-world applications. Moreover, a novel charging choice model is proposed which provides more realistic demand modeling by allowing critical non-linearities in random utility to better describe observed charging behaviors. The results of a case study for the Atlanta metropolitan area imply that work/public charging has a substantial potential market, which can comprise up to 64.5% of the total demand. Out of multiple charging modes, demand for direct-current fast charging (DCFC) is prominent at work/public locations, and it makes up the largest portion of the non-residential demand in all simulation scenarios. Moreover, charging behaviors have significant impacts on the demand distribution. Peak power demand for use of level-2 chargers is 49% to 91% higher among high-risk-sensitive users than among risk-neutral users. Users’ preferences for fast charging rates can change the DCFC demand from 36.4% of the total demand to 53.7% of the total. This study helps to qualitatively analyze the factors that figure in charging demand and their impacts on the demand distribution. The results can be directly used in EVSE planning and electricity load prediction.

A self-powered human-pet interaction system enabled by triboelectric nanogenerator functionalized pet-leash

Amid the increasing popularity of human-pet companionship, wearable electronics that can monitor pets' health and exercise habits in real-time have become more and more prominent. With this comes the urgent need for a sustainable power supply for these devices to support the human-pet interaction system. In this work, a triboelectric nanogenerator functionalized pet leash (TEPL) is designed to harvest abundant mechanical energy from the relative motion between human and pet, which is mainly composed of an embedded TENG, a turntable with a coil spring, and a leash sewn with conductive Ag wires. Electricity is generated when TEPL is pulled out and retracted. The parameters affecting TEPL’s outputs (pull-out distance, frequency, grating-degree of electrode) are systematically studied. Incorporating the power management circuit, not only does the device is equipped with a fast-charging rate for commercial capacitors, it can also power the LED chaplet made by 84 lamps in series connection when co-exercising with dogs. In addition, TEPL is demonstrated to continuously drive various pet wearable electronics, such as acoustic mosquito dispeller, sports bracelet, calorie counter, and pedometer. This work expresses the integration and feasibility of using TENG technology to construct a self-powered human-pet interaction system to satisfy the pursuit of sustainable power supplies.

(Digital Presentation) Sol – Gel Process of Activated Carbon Based Silica Nanostructure Using Rice Husk Template for Supercapacitor Applications

Rice hulls have portrayed large potential in becoming a sustainable biomass source in producing silica, cellulose, and carbon materials, which garnered well-known interest in the middle of researchers. In recent years, silica-based supercapacitors have emerged as leading energy storage devices that can be mostly used in hybrid electric vehicles, memory devices, etc owing to their unique features like fast charge and discharge rate, long cycle life, high power density, high reliability, etc. The objective of the current study is to determine and compare the specific capacitance of pure silica ( SiO2@SP ) and activated carbon added amorphous silica (SiO2 @SA) nanostructures in rice hulls due to the synergistic effects of the sol-gel process. In this study, we have synthesized pure silica SiO2 and activated carbon added amorphous silica (SiO2 @SA) nanostructures using rice hulls template as a silica source via the simple sol-gel method for supercapacitor applications. XRD, FT-IR, and EDX studies characterize that pure silica(SiO2@SP) is present in amorphous form along with activated carbon having a carbon ballades structure in the prepared SiO2@ SA sample. Further, FE-SEM, TEM observation indicates that the prepared sample is consisting of amorphous silica nanospheres added agglomerated carbon nanoparticles having the size of 20 –30 nm. Cyclic voltammetry and galvanostatic charge/discharge studies characterize the supercapacitive behavior of working electrodes fabricated from prepared SiO2@SP and SiO2@ SA nanostructure. The specific capacitances of SiO2@SP nanostructure are about 36,30,28,26,24,23,22,20 and 12 F/g with the current density value of 4, 6, 8,10,12,14,16,18 and 20 A/g, and the specific capacitances of SiO2@ SA nanostructure are about 85,58,48,46,38,34,32, and 26 F/g with the current density value of 4, 6, 8,10,12,14,16,18 and 20 A/g, respectively. The presence of SiO2@SP species in SiO2@SA nanostructure can provide reactive surfaces for the adsorption/desorption charges and it facilitates the charge storage at the surface of the sample. The above results suggested that the prepared SiO2@SA nanostructure has high potential application for comparison than SiO2@SP nanostructure, making electrochemical supercapacitors.

Carbon Nanofiber Decorated Ternary Transition Metal Oxide Anodes for Fast Charging Lithium‐Ion Batteries

Fast charging rate capability of electrochemically active ternary transition metal Ni–Co–Mn oxides (NCMO) anode incorporated with the carbon nanofibers (CNF‐NCMO) is prepared by a simple thermal decomposition of acetylene gas on spherical Ni–Co–Mn oxide particles, and the tap density of the particles is around 1.3 g cm−3. The CNF‐NCMO showed the reversible capacity of 447 mAh g−1 at 10C rate (10 A g−1) in lithium metal half‐cells at room temperature (loading level was 1.4 mg cm−2). However, pristine NCMO only shows a reversible capacity of 124 mAh g−1 at 10C rate. The improved lithium storage and rate capability are mainly ascribed to the conductive CNF networks, reducing the contact and charge transfer resistance between the NCMO samples. Also, these results suggest that the carbon nanofibers act as a buffer layer for preventing the volume expansion during the lithium conversion reactions with the improved structural integrity.

Enabling 100C Fast-Charging Bulk Bi Anodes for Na-Ion Batteries.

It is challenging to develop alloying anodes with ultrafast charging and large energy storage using bulk anode materials because of the difficulty of carrier-ion diffusion and fragmentation of the active electrode material. Herein, a rational strategy is reported to design bulk Bi anodes for Na-ion batteries that feature ultrafast charging, long cyclability, and large energy storage without using expensive nanomaterials and surface modifications. It is found that bulk Bi particles gradually transform into a porous nanostructure during cycling in a glyme-based electrolyte, whereas the resultant structure stores Na ions by forming phases with high Na diffusivity. These features allow the anodes to exhibit unprecedented electrochemical properties; the developed Na-Bi half-cell delivers 379mAhg-1 (97% of that measured at 1C) at 7.7Ag-1 (20C) during 3500 cycles. It also retained 94% and 93% of the capacity measured at 1C even at extremely fast-charging rates of 80C and 100C, respectively. The structural origins of the measured properties are verified by experiments and first-principles calculations. The findings of this study not only broaden understanding of the underlying mechanisms of fast-charging anodes, but also provide basic guidelines for searching battery anodes that simultaneously exhibit high capacities, fast kinetics, and long cycling stabilities.

Large-Scale Li-Ion Battery Research and Application in Mining Industry

The lithium-ion battery (LIB) has the advantages of high energy density, low self-discharge rate, long cycle life, fast charging rate and low maintenance costs. It is one of the most widely used chemical energy storage devices at present. However, the safety of LIB is the main factor that restricts its commercial scalable application, specifically in hazardous environments such as underground coal mines. When a LIB is operating under mechanical and electrical abuse such as extrusion, impact, overcharge and overheating, it will trigger thermal runaway and subsequently cause fire or even an explosion. According to the relevant requirements in IEC60079, the explosion-proof protection of LIB can be adapted to the working environment of high dust and explosive gas environments such as in the mining face of coal production. This paper presents an overview of the LIB-relevant technology, thermal runaway, safety and applications in the general mining industry with implications to establish a theoretical and technical basis for the application of high-capacity LIBs in the industry. These then promote intelligent, safe and efficient production not only for the coal mine industry but also for non-coal applications.

Widespread range suitability and cost competitiveness of electric vehicles for ride-hailing drivers

Transportation network companies provide an increasingly significant share of mobility, which has prompted interest in curbing greenhouse gas emissions in the ride-hailing sector. Vehicle electrification offers the possibility of vast emissions reductions, but a number of factors are thought to constrain this transition. We investigate two such factors – battery electric vehicle (BEV) range and total cost of ownership – from 2019 driving data covering all U.S. drivers on the Lyft platform. We estimate that, for more than 86% of drivers, their daily travel needs can be met by a fully charged BEV with listed range of 250 miles (BEV250) on at least 95% of days. New and pre-owned BEVs both appear to be cost-saving for many drivers. We estimate that a $5,700 BEV purchase subsidy would make new BEVs cost-competitive to gas-powered vehicles for all drivers on the Lyft platform, holding annual mileage and vehicle prices constant. Our results suggest that range and lifetime cost should not be significant barriers to widespread EV take-up in the ride-hailing sector. More generally, they suggest that continued moderate subsidies for BEVs, information interventions, and targeting of such programs to ride-hailing drivers who stand to gain most from them will promote a faster transition in this sector. Driver-targeted outreach and information provision related to EV benefits, as well as expansion of charging availability and fast charging rates through local and federal policy, are additional valuable steps to encourage ride-hailing electrification.

Safety boundary of power battery based on quantitative lithium deposition

There are not perfect ways to solve the lithium metal deposition of the lithium-ion battery during the fast-charging process currently. Moreover, the safety problems caused by lithium deposition are also unfixed. The safety boundary will be a practical guide for battery usage. In this research, batteries designed with different capacities are charged to achieve different lithium deposition and establish prediction data for battery safety boundaries based on the safety performance of the batteries. The quantitative method of lithium deposition combined with the safe behavior of the battery provides an important reference method for the design of fast charging of the battery. What's more excited is that our approach is expanded to provide experience for the manufacturers in battery safety design that can meet the different fast charging rate requirements. The safety boundaries can achieve the best battery safety performance while saving the materials consumed in manufacture from the root.

A Review on the Synthesis of CuCo2O4 Based Electrode Material and their Application in Supercapacitors

Supercapacitors joined of the most promising energy storage systems are extensively studied due to their unique merits, like long-term cycling stability, fast charge rate, and low maintenance cost. it's widely known that the electrochemical performances of supercapacitors are closely associated with the structure and specific extent of the electrode materials. Therefore, many sorts of research are focused on the planning and synthesis of electrode materials with novel shapes and huge surface areas. CuCo2O4 has recently attracted enormous research interest because of the electrode materials for supercapacitors as a result of its inherent advantages including high theoretical capacity, environmental friendliness, natural abundance, and low cost. In practical applications, the CuCo2O4 still suffers from some drawbacks; for example, poor conductivity, relatively low specific capacity, and poor cycling durability. Hence, a comprehensive summary of the recent progress of CuCo2O4-based materials is critical and significant to higher understand the opportunities and challenges that such materials face. during this work, the progress of preparation methods and electrochemical performances of CuCo2O4-based materials is comprehensively reviewed. The aim of this review is to focus on a number of the advances made by CuCo2O4-based electrode materials for supercapacitors and guide future research toward closing the gap between achieved and theoretical capacity, without limiting the loading mass.

A General Multi-Interface Strategy toward Densified Carbon Materials with Enhanced Comprehensive Electrochemical Performance for Li/Na-Ion Batteries.

Fast charging rate and large energy storage are key requirements for lithium-ion batteries (LIBs) in electric vehicles. Developing electrode materials with high volumetric and gravimetric capacity that could be operated at a high rate is the most challenging problem. In this work, a general multi-interface strategy toward densified carbon materials with enhanced comprehensive electrochemical performance for Li/Na-ion batteries is proposed. The mixture of graphene oxide and sucrose solution is sprayed into a water/oil system and furtherly carbonized to get graphene/hard carbon spheres (GHSs). In this material, abundant ingenious internal interfaces between the crystalline graphene and the carbon matrix are created inside the hard carbon spheres. The constructed interfaces can not only work as a pathway for the escape of volatile gas generated during sucrose pyrolysis to prevent the formation of abundant pores, which leads high packing density of 0.910gcm-3 and low surface area of 13.3m2 g-1 , but can also provide a conductive "highway" for ions and electrons. When used as the anode material for both LIBs and sodium-ion batteries (SIBs), the GHS shows the high gravimetric/volumetric reversible capacities, high-rate performance, and low temperature properties simultaneously, implying the great potential application in practical LIBs and SIBs.

A significant enhancement of cycling stability at fast charging rate through incorporation of Li3N into LiF-based SEI in SiOx anode for Li-ion batteries

SiOx has attracted significant attention as an advanced anode material for next-generation lithium-ion batteries for electric vehicles. However, low Li-ion conductivity, chemical instability, morphological inhomogeneity, and the subsequent uneven growth of solid electrolyte interphase (SEI) are still unresolved and hinder its practical application. The LiF-rich SEI obtained using a conventional electrolyte with vinyl carbonate (VC) additive generally exhibits enhanced mechanical rigidity and low ionic conductivity. Herein, we report the use of octadecylamine (ODA) as additional electrolyte additives to enhance the ionic conductivity and physicochemical stability of the SEI by incorporating Li3N into the LiF-based SEI of SiOx anode. The Li3N with high ionic conductivity obtained by addition of ODA provides excellent lithium storage stability and fast charge/discharge performance; the NCM-811||Ti-SiOx@C full cell with VC and ODA additives exhibits approximately 2 times increased capacity retention even after 1000 cycles at 5 C-rate compared to the conventional electrolyte with VC additive only (approximately 5 times compared to the electrolyte without an additive).

Elucidating Cathode Degradation Mechanisms in LiNi0.8Mn0.1Co0.1O2 (NMC811)/Graphite Cells Under Fast Charge Rates Using Operando Synchrotron Characterization

Li-ion batteries capable of extreme fast charging (XFC) are in demand to facilitate widespread electric vehicle (EV) adoption. While the impact of fast charge on the negative electrode has been studied, degradation of state-of-the-art NMC811 under XFC conditions has not been studied in detail. Herein, cathode degradation is probed in NMC811/graphite batteries by analysis of structural and chemical changes for recovered samples previously cycled under XFC conditions and during typical cycling. NMC surface reconstruction, as determined by soft X-ray absorption, was not detected for recovered electrodes. However, bulk redox activity from X-ray absorption near edge structure measurements showed more change in the oxidation state of Ni and Co under the 1C charge rate compared to the 4C rate consistent with the electrochemistry. Increased unit cell volume contraction under the 1C rate as determined by operando X-ray diffraction suggests that higher charge rates may provide a protective effect on the cathode by reducing structural distortion due to less delithiation.

Preparation of Electrode Materials Based on Carbon Cloth via Hydrothermal Method and Their Application in Supercapacitors.

Supercapacitors have the unique advantages of high power density, fast charge and discharge rates, long cycle life, high safety, and reliability, and are increasingly being used for applications including automobiles, rail transit, communication equipment, digital electronics, and aerospace equipment. The supercapacitor industry is currently in a stage of rapid development; great breakthroughs have also been made in improving the performance of supercapacitors and the expansion of their application. Electrode technology is the core of supercapacitors. Transition-metal compounds have a relatively high theoretical capacity and have received widespread attention as electrode materials for supercapacitors. In addition, there is a synergistic effect between the different components of various electrode composite materials. Due to their superior electrochemical performance, supercapacitors are receiving increasing research attention. Flexible supercapacitors have been hailed for their good plasticity, resulting in a development boom. This review article mainly outlines the development process of various electrode materials, including carbon materials, conductive polymers, metal compounds, and composite materials, as well as flexible electrode materials based on carbon cloth.