Loss Of Capacity Research Articles

Deciphering the Interfacial Li-Ion Migration Kinetics of Ni-Rich Cathodes in Sulfide-Based All-Solid-State Batteries.

Nickel-rich layered oxide with high reversible capacity and high working potentials is a prevailing cathode for high-energy-density all-solid-state lithium batteries (ASSLBs). However, compared to the liquid battery system, ASSLBs suffer from poor Li-ion migration kinetics, severe side reactions, and undesired formation of space charge layers, which result in restricted capacity release and limited rate capability. In this work, we reveal that the capacity loss lies in the H2-H3 phase transition period, and we propose that the inconsistent interfacial Li-ion migration is the arch-criminal. We introduce Si doping to stabilize the bulk structure and Li4SiO4 fast ionic conductor coating to regulate the interfacial behaviors between the Ni-rich cathode and sulfide-based solid electrolyte Li6PS5Cl. The modified NCM@LSO-2||LPSCl||Li-In ASSLBs deliver a high reversible capacity of 183.5 mA h g-1 at 0.1C, 30.3% higher than the bare NCM811 electrode. Besides, the interfacial regulation strategy enables the operation at a high rate of 5.0C and achieves a high capacity retention ratio of ∼85.8% after 500 cycles at 1.0C. Furthermore, the underlying mechanisms are well investigated through kinetic analyses and theoretical simulations. This work provides an in-depth understanding on the interfacial degradations between Ni-rich cathodes and sulfide-based all-solid-state electrolytes from the view of kinetic limitations and offers potential solutions.

Decoupling Degradation at the Electrode Interfaces in Prussian White Full Cells

AbstractPrussian blue analogues for sodium‐ion battery cathodes are growing in popularity as next‐generation energy storage devices. Prussian White (PW) with formula NaxFe[Fe(CN)6]y•nH2O is leading the trend, having already been commercialized. However, capacity fade (PW/electrolyte degradation) and safety concerns (cyanide/cyanogen release) still raise concerns. Online electrochemical mass spectrometry, supported by both operando Fourier transform infrared spectroscopy and Mössbauer spectroscopy, is herein used to analyze degradation processes in PW‐based Na‐ion full cells. Apart from the typical cell formation reactions, hydrogen is observed to evolve during cell discharge and evidenced to stem from oxidation of NaH, accumulated upon charge. Over‐oxidation of PW after full desodiation releases CN, which not only forms (CN)2 but also degrades the electrolyte. Loss of CN likely results in a nanometric (≈4 nm) surface‐reconstructed passivation layer on PW, thus inhibiting further degradation. Fundamental understanding of degradation reactions in PW full‐cells, as gathered herein, shows that the aforementioned capacity fade and safety concerns are wholly addressable and hence guides the further development of Na‐ion batteries for wider ranges of applications.

Stability of Alizarin as a Low-Cost Anthraquinone for Aqueous Redox Flow Batteries

Abstract An affordable and sustainable redox-active compound with suitable electrochemical properties is the key for commercializing redox flow batteries. Herein, the stability of the flow battery negolyte, alizarin (1,2- dihydroxyanthraquinone), is studied under different cycling conditions with a ferro/ferricyanide posolyte. The developed cell exhibits an open circuit potential of 1.12 V at 50% state-of-charge and capacity fade rate of 0.73% per day with full state-of-charge window (~ 0 – 99%) cycling. Three capacity fade mechanisms are identified: dimerization of reduced alizarin and a decrease in concentration of alizarin due to precipitation and crossover. Capacity recovery via oxidation of formed dimers is implemented with some success, while leaving precipitation as the dominant capacity fade mechanism.

Towards High-Performance Li-Rich Cathode Materials: from Morphology Design to Electronic Structure Modulation.

Lithium-rich cathode materials (LRMs) have garnered significant interest owing to their high reversible discharge capacity (exceeding 250 mAh g⁻¹), which is attributed to the redox reactions of transition metal (TM) ions as well as the distinctive redox processes of oxygen anions. However, there are still many problems, such as their relatively poor rate performance and voltage fading and hysteresis, hindering their practical applications. Herein, the recent insights into the mechanisms and the latest advancements in the research of LRMs are discussed. Strategies to promote the performance of LRMs are discussed following a top-down approach from the morphology design to electronic structure modulation. Finally, the ongoing efforts in this area are also discussed to inspire more new ideas for the future development of LRMs.

Intramolecular Hydrogen Bonds Weaken Interaction Between Solvents and Small Organic Molecules Towards Superior Lithium-Organic Batteries.

The strong interaction between organic electrode materials (OEMs) and electrolyte components induces a high solubility tendency of OEMs, thus hindering the practical application of lithium-organic batteries. Herein, we propose an efficient strategy for intramolecular hydrogen bonds (HBs) to redistribute the charge of OEMs to weaken the interaction with electrolyte components, thereby suppressing their dissolution. For the designed 2,2',2''-(2,4,6-trihydroxybenzene-1,3,5-triyl) tris (1H-naphtho[2,3-d]imidazole-4,9-dione) (TPNQ) molecule, the intramolecular HBs (O-H…N and N-H…O) reduce the charge density of active sites and alter the charge distribution on the molecular skeleton. As a result, TPNQ shows significantly reduced solubility in both ether- and ester-based solvents. In-situ measurements and theoretical calculations indicate that the O-H…N dominated HB interaction strengthening during the discharging process, which can continuously suppress dissolution. Therefore, the TPNQ cathode displays high cycling stability (no capacity fading over 100 cycles at 0.1 A g-1; 88.4% capacity retention over 1000 cycles at 1 A g-1), fast Li+-storage kinetics (211 mAh g-1 at 2 A g-1), and surprising low-temperature performances (stability cycles 500 times at -60 °C). Our results offer evidence that the intramolecular HBs strategy is promising in developing robust organic electrode materials for rechargeable batteries.

Restructuring of Sodium-Lead Alloys during Charge-Discharge Cycling in Sodium-Ion Batteries

Abstract Sodium-ion batteries (NIBs) are of growing interest due to their expected lower cost than many lithium-ion batteries (LIBs). However, most NIBs suffer from lower volumetric energy density than LIBs. Lead (Pb) can replace hard carbon in the NIB negative electrode to substantially increase its volumetric energy density and has been shown to have no capacity fade over hundreds of cycles in half cells. Pb also experiences 387% volume expansion upon full sodiation, which presumably leads to significant changes in the electrode morphology. In this work, the morphology of Pb and Pb-hard carbon blended electrodes is tracked using scanning electron microscopy. As well, each Na-Pb phase is examined to analyze their physical properties. These analyses show that the Pb particles restructure into ~1 µm particles, even after just a single cycle, and surprisingly do not pulverize the hard carbon in a blended electrode. Single-walled carbon nanotubes appear to be necessary to maintain active material electrical connection.

Operando Investigation of Zr Doping in NMC811 Cathode for High Energy Density Lithium Ion Batteries.

LiNi0.8Mn0.1Co0.1O2 (NMC811) is one of the most promising cathode materials for high energy density Li-ion batteries (LiBs). However, NMC811 suffers from capacity fading during electrochemical cycling because of its structure instability at voltages > 4.2 V vs Li|Li+ due to the known hexagonal H2 → H3 phase transition. Zr doping has proven to be effective in enhancing electrochemical performances of the NMC811. In depth investigations are conducted through operando x-ray diffraction (XRD) and ex-situ x-ray absorption spectroscopy (XAS) measurements to mechanistically understand the benefits of Zr-doping in a NMC811 material when doped during the co-precipitation step. Herein, Zr-doping in NMC811 reduces the formation of the detrimental H3 phase and mitigates the transition metal dissolution upon cycling.

Advanced Balancing of High-Energy Lithium Ion Cells Comprising Lithium-Rich Layered Oxide and a-Si/CuSi Nanowire Using a Cathode Pre-Lithiation Additive

Abstract Advances in lithium-ion battery (LIB) research have strived for high-energy, safe, and sustainable materials. Li-rich Li1.2Ni0.2Mn0.6O2 (LRNM) cathodes have shown great promise with high voltages and excellent specific capacities. Obstacles preventing the viability and commercialization of LRNM are the initial capacity loss of roughly 30% and rapid voltage decay upon cycling. Herein, lithium oxalate (Li2C2O4) is investigated as a pre-lithiation additive to utilize the first-cycle lithium re-intercalation losses of LRNM to compensate the irreversible lithium consumption in graphite and high-capacity a-Si on copper silicide nanowire (a-Si/CuSi NW) anodes. Specifically, the decomposition process of Li2C2O4 as well as the interaction between the electrode components inside the cell are comprehensively examined. This concept allows us to extend the cycle life of graphite||LRNM cells at 1C from less than 500 cycles (142 mAh g-1, 78%) to more than 900 cycles (143 mAh g-1, 82%) before reaching the 80% capacity retention threshold. Finally, LRNM electrodes with a precisely balanced concentration of Li2C2O4 are prepared in order to compensate the high irreversible losses of a-Si/CuSi NW anodes, achieving a capacity retention of almost 50% with a remaining specific capacity of 82 mAh g-1 after 400 cycles in high-energy a-Si/CuSi NW||LRNM lithium-ion cells.

Mitigating Li-Rich Layered Cathode Capacity Loss by Using a Siloxane Electrolyte Additive.

The instability of the electrode-electrolyte interface in high-voltage cathode materials significantly hinders the development of high-energy-density lithium-ion batteries (LIBs). In this study, 1,3-diphenyl-1,1,3,3-tetramethyldisiloxane (DTS) is employed as an electrolyte additive to enhance the cycling stability and capacity retention for Li||LLO (Li-rich layered oxide) batteries operating at 4.8 V. Theoretical calculations show that DTS can preferentially oxidize on the surface of the cathode. The oxidation forms a robust cathode electrolyte interface (CEI) on the LLO surface, significantly mitigating cracking, regeneration, and irreversible phase transitions of the LLO cathode. As anticipated, the Li||LLO batteries with the DTS electrolyte exhibit a capacity retention of 85.4% after 100 cycles at 4.8 V compared to the baseline electrolyte (45.2%). Furthermore, these batteries demonstrate superior capacity retention after 100 cycles at 4.8 V, even with the presence of 1000 ppm of H2O.

High isolation dual band circularly polarized CPW based MIMO antenna with improved diversity performance for WLAN and C band wireless applications

ABSTRACT This paper presents a 2-port MIMO antenna with a CPW feed, designed for dual-band operation with high isolation. We resolved bandwidth and polarization issues in the antenna’s initial CPW-fed design by modifying the radiating patch and incorporating an asymmetrical ground plane. These adjustments enabled dual-band and dual-polarization functionality. The first band, with linear polarization, operates between 2.75 GHz and 2.86 GHz for sub-6 GHz wireless applications, while another band exhibits circular polarization with wide-band resonating at two frequencies, in the (4.7–5.6) GHz and (7.1–8.5) GHz ranges, respectively, covering the entire C-band and suitable for wide-band applications. The antenna, built on a Rogers-5880 substrate (1.57 mm thickness, εr = 2.2, tan δ = 0.0009), offers low loss and excellent thermal stability. The antenna, measuring 45.5 × 27 × 1.57 mm3, attains port isolations of 27 dB and 22.4 dB, with peak realized gains of 2.8 dB and 5.4 dB in the two bands. Furthermore, we analyze the key performance of the MIMO antenna, including the envelope correlation coefficient (ECC), diversity gain (DG), total active reflection coefficient (TARC), and channel capacity loss (CCL), and confirm that they fall within an acceptable range, making it an excellent choice for many portable wireless applications.

Non-Destructive Testing of Concrete Materials from Piers: Evaluating Durability Through a Case Study

Concrete is currently the most used construction material, mainly due to its mechanical strength, chemical stability, and low cost. This material is affected by wear processes caused by the environment, which lead to a reduction in the useful life of the infrastructure in the long term. These wear processes can cause cracks, corrosion of reinforcing steel, loss of load capacity, and loss of concrete section, among other problems. Considering the above, it is necessary to carry out durability studies on concrete to determine the integrity conditions in which the infrastructure is found, the reasons for its deterioration, the environmental factors that affect it, and its useful life under these conditions, and develop restoration or protection plans. Generally, the durability studies include non-destructive testing such as ultrasonic pulse velocity, electrical resistivity, porosity measurement, and capillary absorption rate. These techniques make it possible to characterize the concrete and obtain information such as the total volume of pores, susceptibility to corrosion of the reinforcing steel, decrease in mechanical resistance, cracks, presence of humidity, and aggressive ions inside the concrete. In this work, two durability studies are presented with non-destructive tests carried out on active piers that are 20 and 40 years old. These are located in coastal areas in southern Mexico on the Gulf of Mexico side, with 80% average annual relative humidity, temperatures above 33 °C on average, high concentrations of salts, load handling, vibrations, flora and fauna typical of the marine ecosystem, etc. The results obtained reveal important information about the current state of the piers and the damage caused by the environment over time. This information allowed us to make decisions on preventive actions and develop appropriate and specific restoration projects for each pier.

Evaluating the Performance of the Carrot Slicer Machine

The study was carried out to evaluate the performance of the carrot slicer machine. An experiment was conducted with a multi-factor factorial design under a randomized complete block design. Using the Statistix 8 software, the experiments' collected data were statistically examined. The analysis of variance indicated that the effects of machine speed and feed rate on throughput capacity, efficiency, and percentage loss of the machine were significant at the 5% probability level. The results of the least significance difference pairwise comparison tests revealed that the treatment combination means did not differ significantly from one another at the 5% level. The key physical properties of the carrot including moisture content, angle of repose, bulk density, porosity, coefficient of friction, geometric mean diameter, arithmetic mean diameter, equivalent mean diameter, sphericity, surface area and aspect ratio were obtained as 84.3%, 39.4°, 469.5 kg m-3, 59.8%, 0.78, 47.8 mm, 62.18 mm, 83.7 mm, 0.55, 57.67 cm2, and 0.27, correspondingly. The results showed that the maximum throughput capacity of 621.4 kg h-1 was recorded at 550 rpm machine speed while the minimum throughput capacity of 511.6 kg h-1 was recorded at 350 rpm machine speed. It has been found that the maximum machine efficiency was 96.03% at 550 rpm machine speed whereas the minimum machine efficiency was 92.5% at 350 rpm machine speed. The investigation results revealed that the minimum percentage loss was 4.2% at 550 rpm machine speed whereas the maximum percentage loss was 7.8% at 350 rpm machine speed. The test results suggested that the carrot slicer machine was found to be very effective for processing the vegetable root crop of carrots for end users.

Influence of Breakages of Reinforcing Elements of a Composite Orthotropic Stay Rope on Its Stress-Strain State

The purpose of research is to justify a calculation method for a stay rope of composite fiber structure with a breakage in fiber continuity. Research methodology is in constructing and solving a deformation model of a composite fiber stay rope with continuity breakage of one of its fibers. The calculation method of a stress-strain state of a stay rope of composite fiber structure considering the breakage of one of its fibers is established. The scientific novelty of research is in determining that the length of manifestation of a local disturbance of a stress-strain state of composite stay rope is proportional to a square root of a ratio of tensile modulus of a reinforcing element material and shear modulus of an elastic material that connects them. The practical value of the research is in that the calculation method allows reasonable prediction of a tractive capacity loss of a stay rope as a result of breakage of any of its reinforcing elements. The known value of residual tractive capacity allows reasonable selection of a safety margin for a stay rope, which ensures a sufficient level of reliability of a cable-stayed bridge.

NiFe‐NO3 Layered Double Hydroxide as a Novel Anode for Sodium Ion Batteries

2D materials are emerging materials for energy storage and among these layered double hydroxides (LDHs) seem particularly promising due to their structure, easily adjustable composition, and cheapness. This study marks the first reported application of an LDH, specifically NiFe‐NO3, as anode material in a sodium half‐cell, to the best of our knowledge. Despite an initial loss in capacity, the material demonstrates notable stability, retains a high specific capacity even after 50 discharge/charge cycles (~ 500 mAh/g). The intricate reaction mechanism was explored using various ex‐situ techniques such as DC magnetometry and FTIR, as well as in‐operando X‐ray Absorption Spectroscopy (XAS). The proposed Na‐storage mechanism in NiFe‐NO3 involves an initial irreversible "activation" during the first sodiation, characterized by a phase change reaction that leads to the formation of NiOx and Fe3O4, followed by a reversible mechanism involving both intercalation and conversion in subsequent cycles.

Polythiophene side chain chemistry and its impact on advanced composite anodes for lithium-ion batteries.

In the development of high-performance lithium-ion batteries (LIBs), the design of polymer binders, particularly through manipulation of side-chain chemistry, plays a pivotal role in optimizing electrode stability, ion transport, and adaptability to the volume changes during cycling. In particular, poly[3-(potassium-4-butanoate)thiophene-2,5-diyl] (P3KBT) increases magnetite and silicon capacity and cycling stability. This work explores the impact of polythiophene alkyl sidechain length on anode characteristics, aiming to enhance performance in LIBs. P3KBT and its alkyl chain alternatives, poly[3-(potassium-5-pentanoate)thiophene-2,5-diyl] (P3KPT) and poly[3-(potassium-6-hexanoate)thiophene-2,5-diyl] (P3KHT) were systematically investigated over 300 charge-discharge cycles. The experiments were designed to assess how varying side-chain length affects the stability, ion transport, and capacity retention of the electrodes. The results revealed that P3KHT, with its longer alkyl chain, exhibited superior capacity retention and reduced charge-transfer resistance after 300 cycles compared to its shorter chain analogs. The findings demonstrate that tailored side chains can improve ion transport, structural integrity, and capacity retention, addressing critical challenges in LIBs such as capacity fade and electrode degradation. This research contributes to the development of next-generation LIBs with enhanced performance and reliability.

Enhanced performance of lithium-ion battery cathodes using a composite conductive network of CNTs, GQDs, and GNRs embedded in Li₁.₂Mn₀.₅₄Ni₀.₁₃Co₀.₁₃O₂ (LMNCO)

Lithium-rich Li-ion battery cathode materials are known for their high specific capacities and working potential. However, their practical application is limited by the significant decline in discharge potential and capacity during repeated cycling. In this study, we introduce a highly conductive electrode architecture, encapsulating within carbon nanotubes (CNTs), graphene nano-ribbons (GNRs) and graphene quantum dots (GQDs) to mitigate rapid capacity fading and suppress voltage decay. Three Li1.2Mn0.54Ni0.13Co0.13O2 cathode materials were synthesized. The first sample, pristine Li-rich L1.2Mn0.54Ni0.13Co0.13O2, was synthesized using a nitrate co-precipitation method. The second cathode, GNRs-CNTs@Li1.2Mn0.54Ni0.13Co0.13O2, incorporates a mixture of carbon nanotubes and graphene nanoribbons. The third cathode, GQDs:GNRs-CNTs@Li1.2Mn0.54Ni0.13Co0.13O2), further integrates graphene quantum dots within the graphene nanoribbons and carbon nanotubes matrix. The inclusion of highly conductive GNRs-CNTs and GQDs effectively enhances the electrical conductivity of L1.2Mn0.54Ni0.13Co0.13O2, increasing the specific capacity from 246.95 to 316.94 mAhg−1. Additionally, GQDs prevent side reactions and surface phase transitions, thereby improving thermal stability.

Laser-Induced Regeneration of Spent LiMn2O4 Cathode Into High-Performance Ni-Doped LiMn2O4 Cathode.

The rapid increase in lithium-ion battery (LIB) production, fueled by the rise of electric vehicles, highlights significant challenges in managing end-of-life LIBs, particularly regarding environmental impact and waste management. Traditional recycling methods, such as pyrometallurgical and hydrometallurgical processes, are energy-intensive and consume substantial reagents. In this study, a laser-assisted regeneration method is introduced for LiMn2O4 (LMO) cathodes, enabling in situ Ni doping into spent LMO cathodes (r-LMO-Ni) to enhance electrochemical performance. Surface Ni-doping improves interfacial processes and reduces capacity loss at lower temperatures by creating a new interface with a lower charge transfer energy barrier. The r-LMO-Ni cathode surpasses pristine LMO cathodes, achieving a specific capacity of 112.95mA h g-1 at 1 C and retaining 95.1% of its capacity after 200 cycles at 0 °C. A techno-economic analysis supports the feasibility of this laser-assisted regeneration approach, offering an innovative pathway for upcycling spent cathodes and developing next-generation Mn-based cathodes.

Metasurface absorber for millimeter waves: a deep learning-optimized approach for enhancing the isolation of wideband dual-port MIMO antennas

In this communication, the concept of metasurface absorber is utilized to enhance the isolation in the dual port multiple-input multiple-output (MIMO) antenna specially designed for a wideband millimeter wave operation. The frequency of operation of the designed module is 32.5–42.5 GHz with sufficient gain attributes. The designed metasurface array consists of two circular rings on two different layers. The concept of deep learning is utilized to optimize the dimensional configuration of the metasurface to achieve the maximum absorption of electromagnetic waves in the band of interest. The suppression of mutual coupling by double-ring metasurface is analyzed with the help of the wave theory concept. In contrast to previous decoupling methods using metasurfaces, the suggested metasurface is intended to be in the same plane as the array. The findings demonstrate the capability of effectively separating antenna elements in wideband MIMO antenna without compromising the geometrical complexity. Diversity metrics such as envelope correlation coefficient (ECC), mean effective gain (MEG), channel capacity loss (CCL), and total active reflection coefficient (TARC) for the proposed frequency range are also used to evaluate the performance of the constructed MIMO antenna. The wideband characteristics with a compact configuration make the design MIMO module a suitable candidate for mm-wave applications. The congruence between simulation and measurement confirms the validity of the suggested design.

Highly Stable Aqueous Zn‐Ion Batteries Achieved by Suppressing the Active Component Loss in Vanadium‐Based Cathode

AbstractAqueous zinc–ion batteries (AZIBs) hold significant promise for large‐scale energy storage due to their inherent safety and environmental benefits. However, their practical application is often limited by rapid capacity loss from the dissolution of active cathode materials. Here, an effective strategy is proposed to suppress the active component loss by doping high‐valence Sn4+ in V3O7·H2O (Sn–V3O7·H2O) cathode material to achieve highly stable AZIBs. An impressive capacity retention of 89.3% over 6000 cycles at 5.0 A g−1 and a high specific capacity of 408 mAh g−1 at 0.1 A g−1 are attained. The Sn4+ doping thermodynamically lowers the formation energy of Sn–V3O7·H2O and increases the dissolution energy of VO2+ ions, thereby reinforcing the structural stability and suppressing the vanadium dissolution. Besides, Sn4+ doping enhances electrical conductivity and broadens Zn2+ diffusion channels, significantly accelerating Zn2+ intercalation and deintercalation kinetics. The experimental results are integrated with mechanism analysis and density functional theory calculation to elucidate the dissolution dynamics of V‐based cathodes, and employ X‐ray absorption spectroscopy to reveal the local electronic structures and chemical valences of vanadium during charge/discharge processes, thereby providing comprehensive insights into high‐performance cathode materials for AZIBs.

Capacity fade-aware parameter identification of zero-dimensional model for vanadium redox flow batteries

This study proposes a framework for evaluating the electrochemical performance of a vanadium redox flow battery (VRFB) system. First, a numerical solver for redox flow battery is constructed to represent the multi-physics system through systems of ordinary differential equations, which describe the mass conservation of existing vanadium ions. The present numerical model is validated regarding the voltage by comparing its results with the experimental results of previous studies. Second, we identify the parameters in the governing equations using a genetic algorithm with the present numerical model. We select seven parameters by considering the physical meaning of each parameter related to the electrochemical performance. The voltage for the first charging/discharging cycle and capacity fade data are used to identify the selected parameters. The voltage and capacity fade estimated by the parameters identified using the numerical model align with the previous studies. Finally, we analyze the global sensitivity of the identified parameters in terms of the voltage and capacity fade using the total Sobol’ indices because the high sensitivity confirms that the identified parameters have reliable values. As expected, voltage- and capacity-related parameters show high total Sobol’ indices for the voltage and discharging capacity, respectively. Furthermore, we predict the performance of the VRFBs using the identified parameter set and numerical model during 30-cycle operations. Additionally, the performance is compared according to the current density and vanadium concentration in the electrolyte. The proposed framework can be used to evaluate the electrochemical characteristics of developed VRFBs by identifying parameters related to physical performance, such as voltage and capacity fade. Moreover, the identified parameters can be utilized to predict voltage and capacity performance, enabling the optimization of operating conditions and configurations of VRFBs.