Fast Charging Capability Research Articles

Three‐dimensional Polymers as Organic Cathodes for Affordable and Sustainable Sodium/Potassium‐ion Batteries

AbstractRedox‐active polymers (RAPs) are promising organic electrode materials for affordable and sustainable batteries due to their flexible chemical structures and negligible solubility in the electrolyte. Developing high‐dimensional RAPs with porous structures and crosslinkers can further improve their stability and redox capability by reducing the solubility and enhancing reaction kinetics. This work reports two three‐dimensional (3D) RAPs as stable organic cathodes in Na‐ion batteries (NIBs) and K‐ion batteries (KIBs). Carbonyl functional groups are incorporated into the repeating units of the RAPs by the polycondensation of Tetrakis(4‐aminophenyl)methane and two different dianhydrides. The RAPs with interconnected 3D extended conjugation structures undergo multi‐electron redox reactions and exhibit high performance in both NIBs and KIBs in terms of long cycle life (up to 8000 cycles) and fast charging capability (up to 2 A g−1). The results demonstrate that developing 3D RAPs is an effective strategy to achieve high‐performance, affordable, and sustainable NIBs and KIBs.

Spin-Polarized Surface Capacitance Effects Enable Fe3 O4 Anode Superior Wide Operation-Temperature Sodium Storage.

Fe3 O4 is widely investigated as an anode for ambient sodium-ion batteries (SIBs), but its electrochemical properties in the wide operation-temperature range have rarely been studied. Herein, the Fe3 O4 nanoparticles, which are well encapsulated by carbon nanolayers, are uniformly dispersed on the graphene basal plane (named Fe3 O4 /C@G) to be used as the anode for SIBs. The existence of graphene can reduce the size of Fe3 O4 /C nanoparticles from 150 to 80nm and greatly boost charge transport capability of electrode, resulting in an obvious size decrease of superparamagnetic Fe nanoparticles generated from the conversion reaction from 5 to 2nm. Importantly, the ultra-small superparamagnetic Fe nanoparticles (≈2nm) can induce a strong spin-polarized surface capacitance effect at operating temperatures ranging from -40 to 60°C, thus achieving highly efficient Na-ion transport and storage in a wide operation-temperature range. Consequently, the Fe3 O4 /C@G anode shows high capacity, excellent fast-charging capability, and cycling stability ranging from -40 to 60°C in half/full cells. This work demonstrates the viability of Fe3 O4 as anode for wide operation-temperature SIBs and reveals that spin-polarized surface capacitance effects can promote Na-ion storage over a wide operation temperature range.

Improving the Fast Charging Capability of Lithium-Ion Battery Graphite Anodes by Implementing an Alternative Binder System

An alternative binder system for water-processed graphite anodes for lithium-ion batteries was developed and electrochemically investigated in terms of fast charging capability. The conventionally used binder system for anode coatings, based on CMC and SBR, shows good rheological and mechanical properties, but is limited in its electrochemical performance with respect to high charging currents. However, a marked improvement in fast charging capability is necessary to accelerate the market share of battery electric vehicles. Therefore, we systematically developed an alternative, water-based binder system to improve the fast charging capability of graphite anodes. Thereby, the most promising alternative binder system consisting of alginate, PEO and PVP (2:1:1) showed an improvement in charging performance at 4 C (10 mA cm−2) in the CC-step by more than 150% in 2.5 mAh cm−2 research pouch cells, compared to the reference binder system consisting of CMC and SBR (1:1). The improvement in fast charging capability could be assigned to a reduced ionic pore resistance, as well as a larger active surface area, whereas the pore size distribution, the total surface area, as well as the wettability of the electrode, influence the active surface area. Furthermore, the alternative binder system reveals an improved cycling stability beyond 1,500 cycles.

Solvation Sheath Engineering by Multivalent Cations Enabling Multifunctional SEI for Fast-Charging Lithium-Metal Batteries.

With the pursuit of high energy and power density, the fast-charging capability of lithium-metal batteries has progressively been the primary focus of attention. To prevent the formation of lithium dendrites during fast charging, the ideal solid electrolyte interphase should be capable of concurrent fast Li+ transport and uniform nucleation sites; however, its construction in a facile manner remains a challenge. Here, as Al3+ has a higher charge and Al metal is lithiophilic, we tuned the Li+ solvation structure by introducing LiNO3 and aluminum ethoxide together, resulting in the dissolution of LiNO3 and the simultaneous generation of fast ionic conductor and lithiophilic sites. Consequently, our approach facilitated the deposition of lithium metal in a uniform and chunky way, even at a high current density. As a result, the Coulombic efficiency of the Li||Cu cell increased to over 99%. Moreover, the Li||LiFePO4 full cell demonstrated significantly enhanced cycling performance with a remarkable capacity retention of 94.5% at 4 C, far superior to the 46.1% capacity retention observed with the base electrolyte.

Locally graphitized biomass-derived porous carbon nanosheets with encapsulated Fe3O4 nanoparticles for supercapacitor applications

Waste biomass-derived porous carbons offer significant application prospects, especially in the field of carbon-based supercapacitors, while simultaneously reducing carbon emissions. However, their relatively low conductivity and charge storage capacity have resulted in a low energy density for supercapacitor applications, thereby significantly impeding their large-scale commercial application. At present, comprehensively enhancing the performance of biomass-derived carbon-based supercapacitors (BC-SCs), including energy density, power density, cyclic stability, and rate capability, remains a challenge. To overcome this challenge, Fe3O4 nanoparticles with high conductivity are successfully encapsulated within biomass-derived carbon nanosheets. In conjunction with a localized graphitization strategy, a novel electrode material, locally graphitized biomass-derived hierarchical porous carbon nanosheets with encapsulated Fe3O4 nanoparticles, possessing high specific surface area and conductivity, is successfully prepared. Coupled with TFA electrolyte featuring a high working voltage of 1.4 V, a significant enhancement in the energy density is achieved for BC-SCs, along with ultra-long cyclic durability and excellent fast-charging capabilities. The BC-SCs assembled achieves a high energy density of 15.80 kW kg−1 at a power density of 483 W kg−1. Even at a high power density of 16.40 kW kg−1, the energy density remains at 11.4 Wh kg−1. After 100,000 cycles, the capacitance retention remains remarkably high at 99.6 %. By utilizing hydroquinone as a redox additive, the energy density can be further improved to 32.0 Wh kg−1. This work would pave the way for the large-scale commercialization of BC-SCs.

Breaking Mass Transport Limitations by Iodized Polyacrylonitrile Anodes for Extremely Fast-Charging Lithium-Ion Batteries.

The fast-charging capability of rechargeable batteries is greatly limited by the sluggish ion transport kinetics in anode materials. Here we develop an iodized polyacrylonitrile (I-PAN) anode that can boost the bulk/interphase lithium (Li)-ion diffusion kinetics and accelerate Li-ion desolvation process to realize high-performance fast-charging Li-ion batteries. The iodine immobilized in I-PAN framework expands ion transport channels, compresses the electric double layer, and changes the inner Helmholtz plane to form LiF/LiI-rich solid electrolyte interphase layer. The dissolved iodine ions in the electrolyte self-induced by the interfacial nucleophilic substitution of PF6 - not only promote the Li-ion desolvation process, but also reuse the plated/dead Li formed on the anode under fast-charging conditions. Consequently, the I-PAN anode exhibits a high capacity of 228.5 mAh g-1 (39 % of capacity at 0.5 A g-1 delivered in 18 seconds) and negligible capacity decay for 10000 cycles at 20 A g-1 . The I-PAN||LiNi0.8 Co0.1 Mn0.1 O2 full cell shows excellent fast-charging performance with attractive capacities and negligible capacity decay for 1000 cycles at extremely high rates of 5 C and 10 C (1 C=180 mA g-1 ). We also demonstrate high-performance fast-charging sodium-ion batteries using I-PAN anodes.

3D binder-free nanoarchitecture design of porous silicon/graphene fibers for ultrastable lithium storage

Enhancing the stability and fast-charging capability of battery electrodes is of paramount importance in the field of battery technology. Silicon (Si), renowned for its high specific capacity, has emerged as a promising candidate for anodes. However, the limited structural stability and electron/ion conductivity of silicon-based anodes have raised significant concerns, including fractures and the continuous formation of unstable solid-electrolyte interphase (SEI) layers, leading to rapid capacity decay. In this study, we introduce a comprehensive approach to fabricating a binder-free and free-standing anode electrode paper using a combination technique of employing electrospinning, magnetron sputtering, and chemical vapor deposition (CVD) techniques. This developed paper electrode incorporates a 3D interconnected network of nitrogen-doped vertical graphene nanosheets (VGs) that connect porous carbon fibers (PCFs) with uniformly distributed Si nanoparticles (VGs@Si@PCFs). The as-fabricated VGs@Si@PCFs paper effectively addresses the mechanical and chemical stability issues commonly associated with Si anodes. The VGs@Si@PCFs anode demonstrates a remarkable reversible capacity of 2205 mAh g-1 at 0.1 A g-1 and exhibits exceptional cycling performance with 83.5% capacity retention at 1.0 A g-1 after 3000 cycles. This design leverages the nanoporous carbon fibers and nitrogen-doped vertical graphene nanosheets as flexible and conductive supports, enhancing the robustness and flexibility of the electrode. Additionally, mechanical modeling reveals that the overall Mises strain in the porous VGs@Si@PCFs structure is significantly lower compared to nonporous cases, potentially minimizing low-cycle fatigue. Our free-standing Si/C composite anode introduces a new class of low-strain Si-based materials, showcasing significantly improved stabilities and fast-charging capabilities.

Insights into the kinetics–morphology relationship of 1-, 2-, and 3D TiNb2O7 anodes for Li-ion storage

Understanding the influence of electrode material’s morphology on electrochemical behavior is of great significance for the development of rechargeable batteries, however, such studies are often limited by the inability to precisely control the morphology of electrode materials. Herein, nanostructured titanium niobium oxides (TiNb2O7) with three different morphologies (one-dimensional (1D), two-dimensional (2D), and three-dimensional (3D)) were synthesized via a facile microwave-assisted solvothermal method. The influence of the morphological dimension of TiNb2O7 as electrode material on the electrochemical performance in Li-ion batteries (LIBs) and the underlying correlation with the electrochemical kinetics were studied in detail. 2D TiNb2O7 (TNO-2D) shows a superior rate capability and cycling stability, associated with improved kinetics for charge transfer and Li-ion diffusion, compared to the 1D and 3D materials. Operando X-ray diffraction measurements reveal the structural stability and crystallographic evolution of TNO-2D upon lithiation and delithiation and correlate the Li-ion diffusion kinetics with the lattice evolution during battery charge and discharge. Moreover, carbon-coated TNO-2D achieves enhanced rate capability (205 mAh·g−1 at 50 C) and long-term cycling stability (87% after 1000 cycles at 5 C). This work provides insights into the rational morphology design of electrode materials for accelerated charge transfer and enhanced fast-charging capability, pushing forward the development of electrode materials for high-power rechargeable batteries in future energy storage.

Multistep Improvement of Pilot-Scale 21700 Cells for Increased Fast-Charging Capability: Combining Optimized Electrolyte, Cell Design and Fast-Charging Protocol

In this publication, different cell- and charging parameters (advanced fast-charging protocol, 21700 tab design, electrolyte composition) are changed in a systematic step-by-step approach to reduce charging time while keeping the anode and cathode cell chemistry and electrodes (graphite—NMC 622 full cell) unchanged. Preliminary tests were carried out using 3-electrode full cells with a Li metal reference electrode to identify charging conditions that avoid Li metal deposition. In addition, the effects of the anode potential are investigated in 3-electrode full cells with a Li metal reference electrode. The optimized charging protocols from the 3-electrode full cells were then transferred to 2-electrode pilot-scale 21700 full cells. Two different tab designs (1 × 1 welded tabs and 120 × 125 foil tabs) were used in these cells. To improve the charging time further, an electrolyte with higher ionic conductivity was used under the best conditions from the previous tests. Cross-sectional in situ optical microscopy was used to visualize the transport effects within the anode. In the optimized 21700 cell (advanced fast-charging, 120 × 125 foil tabs, better Li+ transport in the electrolyte), the synergistic effects of the three different optimization steps reduced the charging time to 80% SOC by 46% compared to the baseline cell.

Fast-charging capability of graphite-based lithium-ion batteries enabled by Li3P-based crystalline solid–electrolyte interphase

Fast-charging capability of graphite-based lithium-ion batteries enabled by Li3P-based crystalline solid–electrolyte interphase

Interface design for all-solid-state lithium batteries.

The operation of high-energy all-solid-state lithium-metal batteries at low stack pressure is challenging owing to the Li dendrite growth at the Li anodes and the high interfacial resistance at the cathodes1-4. Here we design a Mg16Bi84 interlayer at the Li/Li6PS5Cl interface to suppress the Li dendrite growth, and a F-rich interlayer on LiNi0.8Mn0.1Co0.1O2 (NMC811) cathodes to reduce the interfacial resistance. During Li plating-stripping cycles, Mg migrates from the Mg16Bi84 interlayer to the Li anode converting Mg16Bi84 into a multifunctional LiMgSx-Li3Bi-LiMg structure with the layers functioning as a solid electrolyte interphase, a porous Li3Bi sublayer and a solid binder (welding porous Li3Bi onto the Li anode), respectively. The Li3Bi sublayer with its high ionic/electronic conductivity ratio allows Li to deposit only on the Li anode surface and grow into the porous Li3Bi sublayer, which ameliorates pressure (stress) changes. The NMC811 with the F-rich interlayer converts into F-doped NMC811 cathodes owing to the electrochemical migration of the F anion into the NMC811 at a high potential of 4.3 V stabilizing the cathodes. The anode and cathode interlayer designs enable the NMC811/Li6PS5Cl/Li cell to achieve a capacity of 7.2 mAh cm-2 at 2.55 mA cm-2, and the LiNiO2/Li6PS5Cl/Li cell to achieve a capacity of 11.1 mAh cm-2 with a cell-level energy density of 310 Wh kg-1 at a low stack pressure of 2.5 MPa. The Mg16Bi84 anode interlayer and F-rich cathode interlayer provide a general solution for all-solid-state lithium-metal batteries to achieve high energy and fast charging capability at low stack pressure.

A fusion method for capacity estimation of fast-charging lithium-ion battery under varied degradation mode

Recently, lithium-ion batteries with fast-charging capability have been gradually equipped in electric products. Capacity estimation specially developed for fast-charging batteries is still an open question, and most of the existing works are proposed for batteries charged under the 1C rate. However, incorrect fast-charging strategies may result in Li plating leading to battery capacity aging rapidly and degradation mode variation. Moreover, unprecise sampling by BMS increases the difficulty of accurately estimating battery capacity in such scenarios. Thus, a fusion prognostic method based on ensemble learning is proposed for the above issues in fast-charging batteries. Firstly, measurement-based health features are extracted from the portion charging phase. Then, the accuracy of the validation dataset-based strategy is proposed to achieve time-varying weight allocation. Finally, a fusion prognostic model is constructed based on the above weight allocation strategy and health features. The effectiveness of the proposed fusion method is verified by a self-design fast-charging battery dataset that maintains stable and reliable performance under sparse sampling and degradation mode variation conditions. In addition, the robustness and adaptability are validated by the comparison experiments with traditional ensemble learning-based methods, in which accuracy is improved by 27.5% minimally.

In-plane isotropic separator-induced highly efficient sodium plating for unlocking the fast-charging capability of anode-free sodium battery at practical conditions

Ether-based electrolytes with excellent reductive stability are compatible with sodium (Na) metal anodes, which enables stable cycling for Na metal batteries even in an anode-free configuration. However, the practical applications of anode-free sodium batteries (AFSBs) with a high theoretical energy density are restricted by the low-rate capability and limited cycle life. Here we demonstrate that the mechanical properties of the separators, which have been overlooked in previous studies, can significantly affect the cycling stability of AFSBs due to the intrinsic softness of Na and the large volume variation of AFSBs during Na plating/stripping. By using various separators including polypropylene (PP), polyethylene (PE), PP/PE/PP tri-layer, and aluminum oxide-coated separators, we find that the balanced elastic moduli of the separator along the machine direction and transverse direction are crucial for enabling highly efficient Na plating and unlocking the 4 C fast-charging capability of the AFSBs at practical conditions including a high cathode active mass loading (13.5 mg/cm2), lean electrolyte addition (8.8 μL/cm2), and no pre-sodiation process. This study provides an important separator design principle for the development of high-rate and long-cycle-life AFSBs.

NbO2 a Highly Stable, Ultrafast Anode Material for Li- and Na-Ion Batteries.

Anode materials with fast charging capabilities and stability are critical for realizing next-generation Li-ion batteries (LIBs) and Na-ion batteries (SIBs). The present work employs a simple synthetic strategy to obtain NbO2 and studies its applications as an anode for LIB and SIB. In the case of the LIB, it exhibited a specific capacity of 344 mAh g-1 at 100 mA g-1. It also demonstrated remarkable stability over 1000 cycles, with 92% capacity retention. Additionally, it showed a unique fast charging capability, which takes 30 s to reach a specific capacity of 83 mAh g-1. For the SIB, NbO2 exhibited a specific capacity of 244 mAh g-1 at 50 mA g-1 and showed 70% capacity retention after 500 cycles. Furthermore, detailed density functional theory reveals that various factors like bulk and surface charging processes, lower ion diffusion energy barriers, and superior electronic conductivity of NbO2 are responsible for the observed battery performances.

Planning of fast charging infrastructure for electric vehicles in a distribution system and prediction of dynamic price

The increasing number of electric vehicles (EVs) has led to the need for installing public electric vehicle charging stations (EVCS) to facilitate ease of use and to support users who do not have the option of residential charging. The public electric vehicle charging infrastructures (EVCIs) must be equipped with a good number of EVCSs, with fast charging capability, to accommodate the EV traffic demand, which would otherwise lead to congestion at the charging stations. The location of these fast-charging infrastructures significantly impacts the distribution system (DS). We propose the optimal placement of fast-charging EVCIs at different locations in the distribution system, using multi-objective particle swarm optimization (MOPSO), so that the power loss and voltage deviations are kept at a minimum. Time-series analysis of the DS and EV load variations are performed using MATLAB and OpenDSS. We further analyze the cost benefits of the EVCIs under real-time pricing conditions and employ an autoregressive integrated moving average (ARIMA) model to predict the dynamic price. The simulated test system without any EVCI has a power loss of 164.36 kW and squared voltage deviations of 0.0235 p.u. Using the proposed method, the results obtained validate the optimal location of 5 EVCIs (each having 20 EVCSs with a 50kWh charger rating) resulting in a minimum power loss of 201.40 kW and squared voltage deviations of 0.0182 p.u. in the system. Significant cost benefits for the EVCIs are also achieved, and an R-squared value of dynamic price predictions of 0.9999 is obtained. This would allow the charging station operator to make promotional offers for maximizing utilization and increasing profits.

Nontraditional Approaches To Enable High-Energy and Long-Life Lithium-Sulfur Batteries.

ConspectusLithium-sulfur (Li-S) batteries are promising for automotive applications due to their high theoretical energy density (2600 Wh/kg). In addition, the natural abundance of sulfur could mitigate the global raw material supply chain challenge of commercial lithium-ion batteries that use critical elements, such as nickel and cobalt. However, due to persistent polysulfide shuttling and uncontrolled lithium dendrite growth, Li-S batteries using nonencapsulated sulfur cathodes and conventional ether-based electrolytes suffer from rapid cell degradation upon cycling. Despite significant improvements in recent decades, there is still a big gap between lab research and commercialization of the technology. To date, the reported cell energy densities and cycling life of practical Li-S pouch cells remain largely unsatisfactory.Traditional approaches to improving Li-S performance are primarily focused on confining polysulfides using electronically conductive hosts. However, these micro- and mesoporous hosts suffer from limited pore volume to accommodate high sulfur loading and the associated volume change during cycling. Moreover, they fail to balance adsorption-conversion of polysulfides during charge-discharge, leading to the formation of massive dead sulfur. Such hosts are themselves electrochemically inactive, which decreases the practical energy density. In contrast, a series of nontraditional approaches, paired with advances in multiscale mechanistic understanding, have recently demonstrated exciting performance outcomes not only in conventional coin cells but also in practical pouch cells.In this Account, we first introduce our novel cathode design strategies to overcome polysulfide shuttling and sluggish redox kinetics in thick S cathodes via selenium-sulfur chemistry and cathode host engineering. Next, we gain a mechanistic understanding of Li-S batteries in various types of electrolytes via a series of spectroscopic, nuclear magnetic resonance, and electrochemical methods. Meanwhile, a novel cathode solid electrolyte interphase encapsulation strategy via nonviscous highly fluorinated ether-based electrolyte is introduced. The established selection rule by investigating how solvating power retards the shuttle effect and induces robust cathode/solid-electrolyte interphase formation is also included. We then discuss how the synergistic interactions between rational cathode structures and electrolytes can be exploited to tailor the reaction pathways and kinetics of S cathodes under high mass loading and lean electrolyte conditions. In addition, a novel interlayer design to simultaneously overcome degradation processes (polysulfide shuttling and lithium dendrite formation) and accelerate redox reaction kinetics is presented. Finally, this Account concludes with an overview of the challenges and strategies to develop Li-S pouch cells with high practical energy density, long cycle life, and fast-charging capability.

Adoption of Dimethoxyethane and 1,3-Dioxolane in Electrolyte for Fast Charging of Li-Ion Battery

In this work, dimethoxyethane (DME) and 1,3-dioxolane (DOL) are studied as the co-solvent of an advanced electrolyte for fast charging of Li-ion batteries by using lithium bis(fluorosulfonyl)imide (LiFSI) as a salt and fluorinated ethylene carbonate (FEC) as an additive. It is shown that even when used with LiFSI and FEC, neither DME nor DOL constitute a suitable electrolyte for Li-ion batteries, either because of their inability to form a robust solid-electrolyte interphase (SEI) with graphite (Gr) anodes or because of their oxidative instability against oxygen released from the delithiated LiNi0.80Co0.10Mn0.10O2 (NCM811) and LiNi0.80Co0.15Al0.05O2 (NCA), respectively. However, using 30% FEC as the co-solvent can make 1:1 DME/DOL mixture compatible with high-voltage Li-ion batteries and combining it with conventional ethylene carbonate (EC) and ethyl methyl carbonate (EMC) significantly enhances the fast charging capability of Li-ion batteries. As a result, an advanced electrolyte composed of 1.2 m (molality) LiFSI 1:1:1:2 DME/DOL/EC/EMC + 10% FEC (all by wt.) offers much improved fast-charging performances in terms of capacity and capacity retention for a 200 mAh Gr/NCA pouch cell, compared with a 1.2 m LiFSI 3:7 EC/EMC baseline electrolyte. AC impedance analysis reveals that the significant improvement is attributed to a much reduced charge transfer resistance, while the advanced electrolyte has little effect on the bulk and SEI resistances.

Scalable Fast-Charging Aligned Battery Electrodes Enabled by Bidirectional Freeze-Casting.

Over the past few years, lithium-ion batteries have been extensively adopted in electric transportation. Meanwhile, the energy density of lithium-ion battery packs has been significantly improved, thanks to the development of materials science and packing technology. Despite recent progress in electric vehicle cruise ranges, the increase in battery charging rates remains a pivotal problem in electrodes with commercial-level mass loadings. Herein, we develop a scalable strategy that incorporates bidirectional freeze-casting into the conventional tape-casting method to fabricate energy-dense, fast-charging battery electrodes with aligned structures. The vertically lamellar architectures in bidirectional freeze-cast electrodes can be roll-to-roll calendered, forming the tilted yet aligned channels. These channels enable directional pathways for efficient lithium-ion transport in electrolyte-filled pores and thus realize fast-charging capabilities. In this work, we not only provide a simple yet controllable approach for building the aligned electrode architectures for fast charging but also highlight the significance of scalability in electrode fabrication considerations.

Tuning dual-atom mediator toward high-rate bidirectional polysulfide conversion in Li-S batteries

An emerging practice in the realm of Li-S batteries lies in the employment of single-atom catalysts (SACs) as effective mediators to promote polysulfide conversion, but monometallic SACs affording isolated geometric dispersion and sole electronic configuration limit the catalytic benefits and curtail the cell performance. Here, we propose a class of dual-atom catalytic moieties comprising hetero- or homo-atomic pairs anchored on N-doped graphene (NG) to unlock the liquid–solid redox puzzle of sulfur, readily realizing Li-S full cell under high-rate-charging conditions. As for Fe-Ni-NG, in-depth experimental and theoretical analysis reveal that the hetero-atomic orbital coupling leads to altered energy levels, unique electronic structures, and varied Fe oxidation states in comparison with homo-atomic structures (Fe-Fe-NG or Ni-Ni-NG). This would weaken the bonding energy of polysulfide intermediates and thus enable facile electrochemical kinetics to gain rapid liquid-solid Li2S4 ↔ Li2S conversion. Encouragingly, a Li-S battery based on the S@Fe-Ni-NG cathode demonstrates unprecedented fast-charging capability, documenting impressive rate performance (542.7 mA h g−1 at 10.0 C) and favorable cyclic stability (a capacity decay of 0.016% per cycle over 3000 cycles at 10.0 C). This finding offers insights to the rational design and application of dual-atom mediators for Li-S batteries.

Influence of different anode active materials and blends on the performance and fast-charging capability of lithium-ion battery cells

To further extent the driving range of battery electric vehicles, an increase of the energy density of lithium-ion battery cells is necessary. One way to increase the energy density is the use of high-capacity electrodes. The challenges for this kind of electrodes are transport limitations, like the long lithium-ion diffusion path to the layers near the substrate of the electrode, leading to performance degradation during cycling. To get a better understanding on how the material selection influences the battery cell performance, various active materials (graphite, silicon, and hard carbon) are investigated, both, pure and in blends and the relation between material, structure and performance is studied. On material level pure silicon active material has a very high electric resistance compared to carbon-based materials. Nevertheless, on electrode level, the high gravimetric energy density, and the round-shaped particle morphology of silicon result into a lower tortuosity and layer thickness, hence, ionic resistance of the electrode. With respect to cell performance, the ionic resistance seems to have a greater impact compared to the charge-transfer and electric resistance. Therefore, silicon-based electrodes show the best performance.