Performance Of Lithium-ion Batteries Research Articles

Structures, electronic properties, and delithiation thermodynamics of the heteroepitaxial α-Al2O3//LiMn2O4 (001) and (111) interfaces

Surface coatings play a pivotal role in enhancing the performance of secondary lithium-ion batteries by mitigating undesirable electrolyte activity towards the cathode materials. Metal oxide candidates have been investigated extensively, with α-Al2O3 emerging as a particularly promising coating material owing to its exceptional mechanical and thermal stability alongside low electrical conductivity. Despite the extensive exploration of this application of α-Al2O3, insight into the interplay between the coating layer and the cathode substrate remains incomplete. To address this lack of knowledge, this study employs density functional theory calculations with a Hubbard Hamiltonian and long-range dispersion corrections (DFT+U-D3) to comprehensively investigate the interfacial geometries, stabilities, and electronic properties of α-Al2O3-coated LiMn2O4 (001) and (111) interfaces of varying thicknesses. The individual surfaces were modelled first before constructing the interfaces. We found that the α-Al2O3 (112¯0) and (0001) surfaces match the LiMn2O4 (001) and (111) facets well, exhibiting {1132} and {3121} configurations, respectively, with corresponding misfits of 2.40 and 2.75 %. We calculated the largest adhesion energies of 0.16 and 0.10 eV/Å2 for monolayers with the {1132} and {3121} configurations, respectively, with the stability decreasing as the thickness of the α-Al2O3 layer increases. Further analysis reveals a minor charge accumulation on the substrate, attributed to charge accumulation on the oxygen atoms that participate in the Al-O bond. In contrast, we observed a depletion of charge on the manganese atoms that form the MnO6 units. The vacancy formation energies increase following partial delithiation, prompting minor charge depletion on neighbouring Mn atoms in the form of charge redistribution. The calculated work function increases with respect to the pristine surfaces, indicating that the coated interfaces are less reactive.

Charge/discharge performance of flame-synthesized TiO2/C composite nanoparticles as anode materials

A flame-synthesized TiO2-based anode material was developed by conducting in-situ composition of TiO2 particles and amorphous carbon particles in a flame. The particle characteristics of the collected composite particles were subsequently examined, and the performances of lithium-ion secondary batteries that used these composite particles as anode materials were measured and evaluated. The aggregates of synthesized and collected particles were confirmed through SEM, EDS, and XRD analysis, revealing a mixture of amorphous carbon particles and TiO2 particles with ranging in size from about 40 to 80 nm. Analysis of the charge/discharge test results on these coin cells indicates that TiO2 and amorphous carbon determine capacity retention and discharge capacity, respectively. Considering both capacity and retention of the cells, optimal flame synthesis conditions were found.

High-Rate Performance of a Designed Si Nanoparticle–Graphite Nanosheet Composite as the Anode for Lithium-Ion Batteries

A silicon nanoparticle–graphite nanosheet composite was prepared via a facile ball milling process for use as the anode for high-rate lithium-ion batteries. The size effect of Si nanoparticles on the structure and on the lithium-ion battery performance of the composite is evaluated. SEM and TEM analyses show a structural alteration of the composites from Si nanoparticle-surrounded graphite nanosheets to Si nanoparticle-embedded graphite nanosheets by decreasing the size of Si nanoparticles from 250 nm to 40 nm. The composites with finer Si nanoparticles provide an effective nanostructure containing encapsulated Si and free space. This structure facilitates the indirect exposure of Si to electrolyte and Si expansion during cycling, which leads to a stable solid–electrolyte interphase and elevated conductivity. An enhanced rate capability was obtained for the 40 nm Si nanoparticle–graphite nanosheet composite, delivering a specific capacity of 276 mAh g−1 at a current density of 1 C after 1000 cycles and a rate capacity of 205 mAh g−1 at 8 C.

Applications of MOFs-Derived Materials in Lithium-Ion Batteries and Sodium-Ion Batteries

Recently, the energy storage system is a popular and widely used system all over the world. It has 5 types of energy storage systems in this paper, and the major topic is the battery energy storage system, including lithium-ion battery (LIB) and sodium-ion battery (SIB). Metal-organic frameworks (MOFs) is widely used in many areas, such as battery design. Thus, for better understanding how MOFs-derived materials are synthesized and what area MOFs-derived materials does increase the performance of LIBs and SIBs, three materials are selected, including Co3O4 hollow dodecahedrons, LiCoO2@C, and amorphous carbon nitride. Synthetic procedures of both MOFs and MOFs-derived materials are detailly discussed. The performance and development of these three materials is measured by comparing their cycle number, efficiency, and specific energy with traditional LIBs and SIBs. In the end, the capability of being a large power supply system is also evaluated by comparing it with the solid gravitational energy storage system, which has high power rating and energy capacity.

Design and Mechanism Study of High-Safety and Long-Life Electrolyte for High-Energy-Density Lithium-Ion Batteries.

Although nonflammable electrolytes are beneficial for battery safety, they often adversely affect the electrochemical performance of lithium-ion batteries due to their poor compatibility with electrodes. Herein, we design a nonflammable electrolyte consisting of cyclic carbonate and 2,2-difluoroethyl acetate (DFEA) solvents paired with several surface-film-forming additives, significantly improving the safety and cycling performance of NMC811||SiOx/graphite pouch cells. The DFEA solvent exhibits not only good flame retardancy but also lower lowest unoccupied molecular orbital (LUMO) energy, promoting the formation of a robust inorganic-rich and gradient-architecture hybrid interface between the SiOx/graphite anode and electrolyte. The double insurance of good flame retardancy of the DFEA solvent and decreased exothermic effects of both bulk electrolyte and DFEA-derived solid electrolyte interphase (SEI) can ensure the high safety of the pouch cell. Moreover, the highly robust SEI can prevent the excessive reduction decomposition of the electrolyte and alleviate the structural decay of the anode, which can restrain the formation of lithium deposition on the anode surface and further suppress the structural decay of NMC materials. This contributes to the unprecedented cycling performance of the NMC811||SiOx/graphite pouch cells with a capacity retention of 80% after 1000 cycles at a 0.33C rate.

Research on the Performance Improvement Method for Lithium-Ion Battery in High-Power Application Scenarios

With the development of technology, high-power lithium-ion batteries are increasingly moving towards high-speed discharge, long-term continuous output, instantaneous high-rate discharge, and miniaturization, and are being gradually developed towards the fields of electric tools, port machinery and robotics. Improving the power performance of batteries can be achieved from multiple dimensions, such as electrochemical systems and battery design. In order to improve the power performance of lithium-ion batteries, this paper proposes design methods from the perspective of electrochemical systems, which include increasing the high-rate discharge capacity and low impedance of the battery. This article also studies the preparation of high-power lithium-ion batteries. This article aims to improve the rate performance of batteries by studying high-performance cathode materials, excellent conductive networks, and high-performance electrolytes. This article successfully screened high-performance cathode materials by comparing the effects of different particle sizes of cathode materials on electrode conductivity and battery internal resistance. By comparing the effects of electrolyte additives under pulse cycling, high-quality electrolyte additive materials were selected. By comparing the effects of different types, contents, and ratios of conductive agents on electrode conductivity, battery internal resistance, high-quality conductive agents, and appropriate ratios were selected. Finally, a 10 Ah cylindrical high-power lithium-ion battery with a specific energy of 110 Wh/kg, pulse discharge specific power of 11.3 kW/kg, an AC internal resistance of ≤0.7 m Ω, a 10C full capacity discharge cycle of over 1700, a 30C full capacity discharge cycle of over 500, and a continuous discharge capacity of 10C–30C, and a pulse discharge capacity of over 100C was prepared.

Effect of explosion impact on the electrical performance and appearance of lithium-ion battery

In this work, the effect of the overpressure and incidence angle of shock waves on lithium-ion battery with various states of charge was studied, and the changes of electrical performance and appearance were measured accordingly. The result shows that the compression from shock wave can lead to the voltage going up and the internal resistance and capacity down; the elevated magnitude of the lithium-ion battery voltage goes up with the state of charge decreasing; the voltage increases and the internal resistance decreases with the overpressure increasing; the magnitude of battery capacity descent depends significantly on the severity of rupture disk cracking, and the capacity declines drastically corresponding to the complete failure of rupture disk; the cracked severity of rupture disk from oblique compression displays more than that from horizontal impact of shock wave; compared to 37Ah batteries, 50Ah batteries have higher safety valve damage thresholds and destruction thresholds, but are more prone to bulging. The conclusions will be of value to the establishment of safety standards for lithium-ion battery.

Li3PO4-Enriched SEI on Graphite Anode Boosts Li+ De-Solvation Enabling Fast-Charging and Low-Temperature Lithium-Ion Batteries.

Li+ de-solvation at solid-electrolyte interphase (SEI)-electrolyte interface stands as a pivotal step that imposes limitations on the fast-charging capability and low-temperature performance of lithium-ion batteries (LIBs). Unraveling the contributions of key constituents in the SEI that facilitate Li+ de-solvation and deciphering their mechanisms, as a design principle for the interfacial structure of anode materials, is still a challenge. Herein, we conducted a systematic exploration of the influence exerted by various inorganic components (Li2CO3, LiF, Li3PO4) found in the SEI on their role in promoting the Li+ de-solvation. The findings highlight that Li3PO4-enriched SEI effectively reduces the de-solvation energy due to its ability to attenuate the Li+-solvent interaction, thereby expediting the de-solvation process. Building on this, we engineer Li3PO4 interphase on graphite (LPO-Gr) anode via a simple solid-phase coating, facilitating the Li+ de-solvation and building an inorganic-rich SEI, resulting in accelerated Li+ transport crossing the electrode interfaces and interphases. Full cells using the LPO-Gr anode can replenish its 80 % capacity in 6.5 minutes, while still retaining 70 % of the room temperature capacity even at -20 °C. Our strategy establishes connection between the de-solvation characteristics of the SEI components and the interfacial structure design of anode materials for high performance LIBs.

Parametric investigation of battery thermal management system with phase change material, metal foam, and fins; utilizing CFD and ANN models

The focus on developing an effective battery thermal management system (BTMS) to maintain optimal temperatures for lithium-ion batteries (LIBs), especially in electric vehicle (EV) applications, has grown significantly. The effective BTMS not only enhances the cooling performance of LIBs but also contributes to increased passenger safety and mileage of EVs. This study investigates BTMS configurations with fins, metal foam, and phase change material (PCM) to minimize temperature of battery during 3C discharging in varying conditions. Additionally, the study explores the impact of different BTMS material combinations and various fins lengths on system performance as a parametric investigation. Moreover, to streamline the analysis process and introduce novelty, artificial intelligence is explored as an alternative to computational fluid dynamics for predicting liquid fraction of PCM and temperature of battery, enhancing the innovative aspect of this study. Numerical simulations, using a non-equilibrium thermal model for metal foam modeling, reveal that the fourth case, integrating all three passive approaches, maintains the lowest temperature and enhances LIB cooling. The optimum BTMS shows a reduction of 3 K compared to BTMS utilizing pure PCM. During discharge process, the temperature difference in the battery decreases by approximately 75 % and 66 % in the fourth case compared to the first case (with pure PCM) under normal and harsh environmental conditions, respectively. Applying copper metal foam and copper fins yields the best results in reducing battery temperature. Increasing the length of fins and adding more fins effectively lower the battery temperature. Finally, an artificial neural network model is developed using the backpropagation learning technique coupled with the gradient descent optimization algorithm. The model exhibits excellent predictive capabilities, achieving high R-squared values of 0.98 for PCM liquid fraction and 0.99 for battery temperature.

An Adaptive Modeling Method for the Prognostics of Lithium-Ion Batteries on Capacity Degradation and Regeneration

Accurate prediction of remaining useful life (RUL) is crucial to the safety and reliability of the lithium-ion battery management system (BMS). However, the performance of a lithium-ion battery deteriorates nonlinearly and is heavily affected by capacity-regeneration phenomena during practical usage, which makes battery RUL prediction challenging. In this paper, a rest-time-based regeneration-phenomena-detection module is proposed and incorporated into the Coulombic efficiency-based degradation model. The model is estimated with the particle filter method to deal with the nonlinear uncertainty during the degradation and regeneration process. The discrete regeneration-detection results should be reflected by the model state instead of the model parameters during the particle filter-estimation process. To decouple the model state and model parameters during the estimation process, a dual-particle filtering estimation framework is proposed to update the model parameters and model state, respectively. A kernel smoothing method is adopted to further smooth the evolution of the model parameters, and the regeneration effects are imposed on the model states during the updating. Our proposed model and the dual-estimation framework were verified with the NASA battery datasets. The experimental results demonstrate that our proposed method is capable of modeling capacity-regeneration phenomena and provides a good RUL-prediction performance for lithium-ion batteries.

A flame‐retardant, dendrite‐inhibiting sandwich separator prepared by electrospinning for high‐performance and safety lithium batteries

AbstractAs the “safety switch” of lithium batteries, the separator controls the electrochemical performance and safety performance of lithium batteries. However, highly flammable and easy to induce lithium dendrite generation of commercial polyolefin pose a huge safety hazard for current commercial lithium‐ion batteries. Therefore, developing a flame‐retardant, lithium dendrite‐inhibiting separator can achieve further leap in the lithium battery industry. A “sandwich” separator (SPS‐B) is designed by integrating silk fibroin (SF), decabromodiphenyl ethane, and polyvinyl alcohol through electrospinning. SPS‐B shows excellent flame‐retardant properties through a free radical trapping mechanism. Moreover, the SPS‐B demonstrated satisfactory capability of suppressing lithium dendrites by constructing Li3N‐SEI with high ionic conductivity and high strength, and the secondary structure β‐sheets of SF can inhibit the “tip effect” of lithium dendrites, which enables efficient lithium plating/stripping in Li//Li and Li//Cu cells. In addition, the enhanced porosity, electrolyte affinity of SPS‐B promotes excellent electrochemical performance with enhanced discharge capacity and reduced concentration polarization. Finally, fire risk of soft‐pack batteries are evaluated by continuous external heating. Compared with commercial separator, soft‐pack batteries with SPS‐B show much lower heat release rate, peak temperature and flue gas release rate, further confirming the effectiveness of SPS‐B in reducing fire risk. Overall, the SPS‐B provides a satisfactory way to develop high‐performance and superior safety lithium batteries.

전기자동차 배터리 냉각 플레이트의 유동 형상에 따른 냉각 성능에 관한 연구

The performance of lithium-ion batteries in electric vehicles is significantly affected by temperature. To ensure battery stability and extend its lifespan, an effective cooling system must be developed for heat dissipation. Therefore, researchers are focusing on liquid-cooled systems that use fluids with higher thermal conductivities compared with conventional air-cooling systems. However, studies regarding the flow shapes of crucial cooling plates in indirect liquid-cooling systems are scarce. In this study, the optimal flow shape of cooling plates with high cooling performance for dissipating heat generated during battery charging and discharging is determined. Four models with different structural features are analyzed via computational fluid dynamics simulations and then validated experimentally. Model 1, which features a small stagnation region, exhibits better cooling performance compared with Model 2, which features smoother curved flow paths. Models with large stagnant regions demonstrate inferior cooling performance, which is attributed to the effect of heat absorption, based on the residence time of the coolant in the cooling plate. Improvement in cooling efficiency is confirmed, which implies the feasibility of applying the model to enhance the performance of electric vehicles in the future.

Chemical prelithiation of SiOx/Gr anode for improved cycling performance in lithium-ion batteries

Owing to its high specific capacity and excellent cycling performance, SiOx is an appealing alternative to traditional graphite anodes. In order to increase the anode's cycling stability, this work demonstrates the chemical prelithiation of SiOx/Gr anode for real-world applications. The highest ICE obtained is 98.8 % using the chemical prelithiation method for half cell. The prelithiated anode was characterized using various techniques, and the viability of the process was tested using a pouch cell assembly, demonstrating enhanced capacity compared to the pristine pouch cell. This research has implications for portable electronics, electric vehicles, renewable energy storage, and other applications requiring high-capacity and long-lasting batteries.

Construction of strengthened crosslinked polymer coating using liquid-like nanoparticle on polyphenylene sulfide nonwoven as separator: Improved cycling performance in lithium-ion battery

Nonwoven-based separators have aroused widespread interest in the development of high-power lithium-ion battery (LIB). However, their commonly used coating, gel polymer electrolyte, is easily to shed off from the substrate during long-term swollen by electrolyte, thus further leading to micro-short circuit phenomenon and poor cycling performance. In this study, strengthened three-dimensional (3D) crosslinked coatings with different ratios of silica-based nanofluid were constructed on polyphenylene sulfide (PPS) nonwoven to give composite separators 3D. Compared with traditional nanoparticle, silica-based nanofluid has liquid-like property and is less prone to aggregation in polymer matrix. Importantly, amine terminal groups can be introduced when preparing fluid molecules, which will react with fluorinated polymer matrix to give strengthened 3D crosslinked coating. When the ratio of PVDF-HFP: fluid is fixed at 10:1, the porosity, electrolyte uptake and wettability, electrochemical performance of separator are found to display the optimum value, which finally endow battery with better discharge capacity (160.3 mAh g−1, 0.2 C). In addition, this composite separator is discovered to own superior tensile strength and Young’s modulus. This strengthened structure also makes separator withstand the oxidative decomposition potential up to 5.32 V and provides battery with excellent discharge performance retention (98.5%) even after 100 cycles. Therefore, this study will pioneer a new avenue for separator to realize higher mechanical and cycling performance.

Dual-modified LiNi0.8Co0.1Mn0.1O2 cathode materials with lithium conducting hybrid oligomer and single-walled carbon nanotube for improving electrochemical performance and thermal stability of lithium-ion batteries: A novel approach for high-power and high-safety applications

In this study, we investigated the synergetic effect of a novel lithium-ion conducting hybrid oligomer [N, N′-bismaleimide-4, 4′-diphenylmethane (BMI), lithiated trithiocyanuric acid (Li-TCA) and Jeffamine®-M1000 (JA®); Li-BTJ] coating layer on a nickel-rich LiNi0.8Co0.1Mn0.1O2 (NCM811) cathode material wrapped with highly electron-conductive single-walled carbon nanotubes (SWCNTs) to enhance electrochemical performance and thermal stability for high-power and high-safety lithium-ion batteries (LIBs). Morphological analyses using scanning electron microscopy/energy dispersive spectroscopy and transmission electron microscopy showed that the NCM811 active material surface was uniformly coated with a hybrid oligomer to form NCM811@Li-BTJ, which was subsequently wrapped with SWCNTs (NCM@Li-BTJ/SWCNT composite cathode). CR2032 coin-type cells with optimized NCM811@1 wt% Li-BTJ/0.2 wt% SWCNT composite electrodes delivered a significantly enhanced capacity retention (CR) of 90.1 % relative to that of bare NCM811 electrodes (CR: 82.1 %) at 1C for 200 cycles from 2.8 to 4.3 V (vs. Li/Li+). Electrochemical impedance spectroscopy and cyclic voltammetry revealed that this superior cycling performance resulted from a lower charge transfer resistance (Rct: 96.2 vs. 324.3 Ω) and a lower polarization voltage (∆V: 0.243 vs. 0.411 V vs. Li/Li+). The in-situ micro-calorimetric results presented the total heat generation (Qt) values of the coin cells with the delithiated NCM811@Li-BTJ and NCM@Li-BTJ/SWCNT electrodes at 5C and 35 °C were substantially lower by ~9.3 % and ~ 14.6 %, respectively, compared to the bare NCM811 counterpart, indicating that the surface modifications on the NCM811 active materials could prevent the LIBs' thermal instability. Furthermore, X-ray photoelectron spectroscopy studies revealed that the Li-BTJ hybrid oligomer coating layer effectively suppressed the formation of residual Li side products such as Li2CO3 evidently on the surface of the NCM811 active material particles, thereby inhibiting undesirable side reactions. Post-mortem analyses of the dual-modified NCM811 electrode after cycling revealed that the microstructure and particle morphology of the NCM composite cathode material were extensively maintained through the synergistic effects of the Li-BTJ ion-conductive and SWCNTs electron-conductive agents.

State of health (SOH) assessment for LIBs based on characteristic electrochemical impedance

With the continuous development of high energy density cell technology, the electric transport industry proposed higher requirements for the accuracy and real-time performance of automotive lithium batteries (LIBs) health status assessment. A state of health (SOH) assessment is suggested based on electrochemical impedance at characteristic frequency in the study. The distribution of relaxation time is used to deconstruct the internal electrochemical reaction of the battery and the impedance value of electrochemical process is quantified as a feature to avoid the effect of state of charge (SOC) in the evaluation. The imaginary part of impedance feature is applied to characterize the internal temperature of the lithium battery based on the analysis of impedance differences. Thus, the correlation between the state of health and impedance characteristics is examined to obtain the SOH assessment model of lithium battery in the full SOC and wide temperature spectrum. In conclusion, the assessment demonstrates an exceptional goodness-of-fit, with an accuracy of 0.99 in evaluating the SOH of LIBs and internal temperature, thereby indicating the robustness and reliability of the approach.

Ionic liquid-based self-healing gel electrolyte for high-performance lithium metal batteries

The gel electrolytes with self-healing function are being considered as promising replacement for traditional liquid electrolytes in lithium metal batteries due to their excellent battery safety, high energy density and minimum electrolyte damage. However, balancing self-healing, conductivity and mechanical properties remains a challenge for their practical application. Herein, a new ion liquid-based self-healing gel polymer electrolyte (IL-SHGPE) is introduced. The electrolyte was synthesized via UV-induced cross-linking of a polymer containing quadruple hydrogen bond units and 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (BMIM-TFSI) ion liquid. The resultant IL-SHGPE demonstrates exceptional self-healing ability (with 95% healing efficiency within 30 min), excellent thermal stability over a wide temperature range up to 410 °C. It also exhibits impressive mechanical strength with 41.3% elongation and 1.9 MPa tensile stress, room temperature ionic conductivity of 1.29 × 10−3 S/cm, and a wide electrochemical stability window of 5.18V (vs Li/Li+). Lithium metal batteries with this electrolyte showed an initial discharge capacity of 139 mAh g−1 at 1C rate, and a capacity retention of 88.3% after 200 cycles. Therefore, this work provides a significant exploration for balancing self-healing ability, mechanical attributes, and electrochemical performance of lithium batteries, and thus contributing valuable insights towards the development of high-performance self-healing gel electrolytes for lithium metal batteries.

Study on the effect of low-temperature cycling on the thermal and gas production behaviors of Ni0.8Co0.1Al0.1/graphite lithium-ion batteries

With their high energy density and long cycle life, lithium-ion batteries (LIBs) are currently the most promising electrochemical energy storage system for electric vehicles. However, their safety and cycling performance can be significantly compromised in low-temperature environments due to lithium plating and other factors. Therefore, it is essential to study the safety of aging batteries. In this study, we focused on a commercially available high-specific-energy Ni0.8Co0.1Al0.1 cathode system battery and simulated the aging of the battery by long-term cycling at 0 ℃. This study compares and analyzes the samples on the basis of the previous ones in terms of heat production power, thermal runaway (TR) characteristics and gas production characteristics. It reveals the influence of low-temperature aging on the comprehensive performance of lithium batteries in a more comprehensive way. The results show that the charging pattern of all three characteristics is related to the aging degree of the battery. In terms of the thermal characteristics, the relative change in specific heat capacity of the aged battery is only between 0.32 % and 1.08 % compared to that of a fresh battery, so the effect of ageing on the specific heat capacity of the battery is negligible. The average heat generation power of batteries with different state of health (SOH) is not monotonically increasing with the decrease of SOH, the threshold of dramatic increase is SOH = 80 %. In terms of TR characteristics, the onset temperature of exothermic reactions (TOER) of aged batteries is significantly lower than that of fresh batteries. With the decrease of SOH, TOER also decreases gradually. Compared with batteries with different SOHs, the more seriously aged the battery safety valve opens earlier, and the TR occurs earlier. In terms of the TR gas production characteristics, the more severely aged the battery, the earlier the safety valve opens compared to a fresh battery. The most gas is produced when SOH = 70 %, which increases the risk of catastrophic damage.

Indium Nitride Nanowires: Low Redox Potential Anodes for Lithium-Ion Batteries.

Advanced lithium-ion batteries (LIBs) are crucial to portable devices and electric vehicles. However, it is still challenging to further develop the current anodic materials such as graphite due to the intrinsic limited capacity and sluggish Li-ion diffusion. Indium nitride (InN), which is a new type of anodic material with low redox potential (<0.7V vs Li/Li+) and narrow bandgap (0.69eV), may serve as a new high-energy density anode material for LIBs. Here, the growth of 1D single crystalline InN nanowires is reported on Au-decorated carbon fibers (InN/Au-CFs) via chemical vapor deposition, possessing a high aspect ratio of 400. The binder-free Au-CFs with high conductivity can provide abundant sites and enhance binding force for the dense growth of InN nanowires, displaying shortened Li ion diffusion paths, high structural stability, and fast Li+ kinetics. The InN/Au-CFs can offer stable and high-rate Li delithiation/lithiation without Li deposition, and achieve a remarkable capacity of 632.5 mAh g-1 at 0.1 A g-1 after 450 cycles and 416 mAh g-1 at a high rate of 30 A g-1. The InN nanowires as battery anodes shall hold substantial promise for fulfilling superior long-term cycling performance and high-rate capability for advanced LIBs.

Research on the heating effect evaluation of the electromagnetic induction heating system at low temperature based on the electrochemical-thermal coupling model

The extremely fast electromagnetic induction heating system (EIHS) was recently introduced to improve the poor charge and discharge performance of lithium-ion batteries (LiBs) at low temperature. In this work, aimed to investigate the heating effect of EIHS, the accurate electrochemical-thermal coupling model, validated against the charging capacity calibration with various C-rates and HPPC tests at different environments, was developed in depth to reflect the electrochemical and heat transfer behaviors of the LiB exposed to external cool air during the electromagnetic induction heating process. When the copper coil was subjected to a sinusoidal alternating current (SAC) excitation at 10 A, 3 kHz, the LiB can be warmed up to 293.15 K from 243.15 K within 742 s with an even heat generation inside the LiB. The impact of the SAC parameters on the needed heating time was illustrated with time maps, a series of contours suggested that the heating velocity increase with the increase of both the amplitude and frequency. As compared with the low-temperature state, the internal resistance had a more than 3-fold decrease, which can improve the discharging voltage platform and terminal voltage output, thus increasing the pulse power and usable capacity. Neither noticeable capacity retention difference before and after the heating cycles nor obvious capacity loss discrepancy between the normal charge-discharge and heating cycle tests was found at the end of the 200 heating cycles, so the EIHS can achieve a good tradeoff among temperature rising effect, working behaviors and LiB cycle lifespan, which had a considerable potential to enhance the applicability of EVs (electric vehicles) in frigid weather. Moreover, a better heat transfer condition, higher material thermal conductivity and lower specific heat capacity play an important positive role on the improvement of temperature rising performance.