A Review of Degradation Mechanisms and Recent Achievements for Ni-Rich Cathode-Based Li-Ion Batteries

The growing demand for sustainable energy storage devices requires rechargeable lithium-ion batteries (LIBs) with higher specific capacity and stricter safety standards. Ni-rich layered transition metal oxides outperform other cathode materials and have attracted much attention in both academia and industry. Lithium-ion batteries composed of Ni-rich layered cathodes and graphite anodes (or Li-metal anodes) are suitable to meet the energy requirements of the next generation of rechargeable batteries. However, the instability of Ni-rich cathodes poses serious challenges to large-scale commercialization. This paper reviews various degradation processes occurring at the cathode, anode, and electrolyte in Ni-rich cathode-based LIBs. It highlights the recent achievements in developing new stabilization strategies for the various battery components in future Ni-rich cathode-based LIBs

Determination of state-of-charge dependent diffusion coefficients and kinetic rate constants of phase changing electrode materials using physics-based models

The simplified gravimetric intermittent titration technique (GITT) model, which was first proposed by Weppner and Huggins in 1977, remains a popular method to determine the solid-state diffusion coefficient (D1) and the electrochemical kinetic rate constant (k). This is despite the model having been developed on the premise of a single-slab electrode and other gross simplification which are not applicable to modern-day porous battery electrodes. Recently however, more realistic and conceptually descriptive models have emerged, which make use of the increased availability of computational power. Chief among them is the P2D model developed by Newman et al., which has been validated for various porous battery electrodes. Herein, a P2D GITT model is presented and coupled with grid search optimization to determine state-of-charge (SOC) dependent D1 and k parameters for a sodium-ion battery (SIB) cathode. Using this approach, experimental GITT steps could be well fitted and thus validated at different SOC points. This work demonstrates the first usage of the P2D GITT model coupled with optimization as an analytical method to derive and validate physically meaningful parameters. The accurate knowledge of D1 and k as a function of the SOC gives further insight into the SIB intercalation dynamics and rate capability

Fabrication and interfacial characterization of Ni-rich thin-film cathodes for stable Li-ion batteries

Ni-rich LiNi0.6Co0.2Mn0.2O2 (NCM) and LiNbO3-protected LiNi0.6Co0.2Mn0.2O2 (NCM) thin-film cathodes have been prepared by radio frequency (RF) magnetron sputtering. Electrochemical investigations show enhanced stability of LiNbO3-protected cathodes compared with bare LiNi0.6Co0.2Mn0.2O2. The interfacial interaction of LiNbO3 and LiNi0.6Co0.2Mn0.2O2 layers has been investigated by XPS depth profiling and demonstrated different cathode electrolyte interface (CEI) film formation processes at the electrodes. The results elaborate on the interaction between LiNbO3 and LiNi0.6Co0.2Mn0.2O2, emphasizing the role of the LiNbO3 layer in improving the cycling performance of Ni-rich cathodes

Applicability of heat generation data in determining the degradation mechanisms of cylindrical li-ion batteries

The applicability of heat generation data obtained after cylindrical Li-ion cells discharging with a constant current was analyzed thoroughly to determine cell degradation mechanisms. Different commercial and noncommercial cylindrical Li-ion cells, wherein graphite was used for negative electrode creation, were considered in this study and the degradation mechanisms were analyzed during cycling and storage. The heat generation in the cylindrical cells was estimated using heat flux and temperature measurements of the cell surface. The results obtained using analysis of the heat generation data were compared with those obtained using differential voltage analysis. The use of the heat generation data was shown to improve the detection and separation of the degradation mechanisms in Li-ion batteries during cycling and storage. The differential curve, which is based on the heat generation data, was proposed to investigate the degradation mechanisms. Moreover, the effects of the C-rate current and temperature on the form of the proposed differential curve were evaluated

Enhanced sulfur utilization in lithium-sulfur batteries by hybrid modified separators

The extraordinary energy density and low cost enable lithium-sulfur (Li-S) batteries to be a promising alternative to traditional energy storage systems. The principal hurdle facing Li-S batteries is the unsatisfactory utilization of sulfur cathodes. The detrimental shuttle issue of polysulfides and the sluggish charge transfer kinetics result in quick capacity degradation of Li-S batteries. An MFLC hybrid material composed of manganese-iron layered double hydroxides (Mn-Fe LDH) and carbon nanotubes (CNT) has been developed. Such heterostructure combines the advantages of effective chemical bonding of Mn-Fe LDH towards polysulfides with the high conductivity of CNT. When modified on a polypropylene (PP) separator, the hybrid material is proven to significantly inhibit the shuttle issue of polysulfides and accelerate their redox reaction kinetics. Li-S batteries with MFLC-modified separators revealed considerably improved electrochemical performance. A high initial capacity of 1138 mA h g−1 and 70 % capacity retention after 200 cycles were achieved at 0.2 C. The enhanced sulfur utilization can be directly evaluated from the discharge voltage plateaus. The results indicate a new solution for the practical application of Li-S batteries and provide a simple approach to determine the efficiency of sulfur utilization

Overpotential analysis of graphite-based Li-ion batteries seen from a porous electrode modeling perspective

The overpotential of Li-ion batteries is one of the most relevant characteristics influencing the power and energy densities of these battery systems. However, the intrinsic complexity and multi-influencing factors make it challenging to analyze the overpotential precisely. To decompose the total overpotential of a battery into various individual components, a pseudo-two-dimensional (P2D) model has been adopted and used for electrochemical simulations of a graphite-based porous electrode/Li battery. Analytical expressions for the total overpotential have been mathematically derived and split up into four terms, associated with the electrolyte concentration overpotential, the Li concentration overpotential in the solid, the kinetic overpotential, and the ohmic overpotential. All these four terms have been separately analyzed and are found to be strongly dependent on the physical/chemical battery parameters and the reaction-rate distribution inside the porous electrode. The reaction-rate distribution of the porous electrode is generally non-uniform and shows dynamic changes during (dis)charging, resulting in fluctuations in the four overpotential components. In addition, the disappearance of the phase-change information in the voltage curve of the graphite-based porous electrode/Li battery under moderate and high C-rates is ascribed to the Li concentration overpotential among solid particles, resulting from the non-uniform reaction-rate distribution

Interface Aspects in All‐Solid‐State Li‐Based Batteries Reviewed

Extensive efforts have been made to improve the Li-ionic conductivity of solid electrolytes (SE) for developing promising all-solid-state Li-based batteries (ASSB). Recent studies suggest that minimizing the existing interface problems is even more important than maximizing the conductivity of SE. Interfaces are essential in ASSB, and their properties significantly influence the battery performance. Interface problems, arising from both physical and (electro)chemical material properties, can significantly inhibit the transport of electrons and Li-ions in ASSB. Consequently, interface problems may result in interlayer formation, high impedances, immobilization of moveable Li-ions, loss of active host sites available to accommodate Li-ions, and Li-dendrite formation, all causing significant storage capacity losses and ultimately battery failures. The characteristic differences of interfaces between liquid- and solid-type Li-based batteries are presented here. Interface types, interlayer origin, physical and chemical structures, properties, time evolution, complex interrelations between various factors, and promising interfacial tailoring approaches are reviewed. Furthermore, recent advances in the interface-sensitive or depth-resolved analytical tools that can provide mechanistic insights into the interlayer formation and strategies to tailor the interlayer formation, composition, and properties are discussed

The NKG2D Ligands RAE-1δ and RAE-1ε Differ with Respect to Their Receptor Affinity, Expression Profiles and Transcriptional Regulation

BACKGROUND: RAE-1 is a ligand of the activating receptor NKG2D expressed by NK cells, NKT, γδT and some CD8(+)T lymphocytes. RAE-1 is overexpressed in tumor cell lines and its expression is induced after viral infection and genotoxic stress. We have recently demonstrated that RAE-1 is expressed in the adult subventricular zone (SVZ) from C57BL/6 mice. RAE-1 is also expressed in vitro by neural stem/progenitor cells (NSPCs) and plays a non-immune role in cell proliferation. The C57BL/6 mouse genome contains two rae-1 genes, rae-1δ and rae-1ε encoding two different proteins. The goals of this study are first to characterize the in vivo and in vitro expression of each gene and secondly to elucidate the mechanisms underlying their respective expression, which are far from known. PRINCIPAL FINDINGS: We observed that Rae-1δ and Rae-1ε transcripts are differentially expressed according to tissues, pathological conditions and cell lines. Embryonic tissue and the adult SVZ mainly expressed Rae-1δ transcripts. The NSPCs derived from the SVZ also mainly expressed RAE-1δ. The interest of this result is especially related to the observation that RAE-1δ is a weak NKG2D ligand compared to RAE-1ε. On the contrary, cell lines expressed either similar levels of RAE-1δ and RAE-1ε proteins or only RAE-1ε. Since the protein expression correlated with the level of transcripts for each rae-1 gene, we postulated that transcriptional regulation is one of the main processes explaining the difference between RAE-1δ and RAE-1ε expression. We indeed identified two different promoter regions for each gene: one mainly involved in the control of rae-1δ gene expression and the other in the control of rae-1ε expression. CONCLUSIONS/SIGNIFICANCE: RAE-1δ and RAE-1ε differ with respect to their function and the control of their expression. Immune function would be mainly exerted by RAE-1ε and non-immune function by RAE-1δ

Observation of triple J/ψ meson production in proton-proton collisions

Data availability: Tabulated results are provided in the HEPData record for this analysis71. Release and preservation of data used by the CMS Collaboration as the basis for publications is guided by the CMS policy as stated in CMS data preservation, re-use and open access policy.Code availability: The CMS core software is publically available at https://github.com/cms-sw/cmssw.Copyright . Protons consist of three valence quarks, two up-quarks and one down-quark, held together by gluons and a sea of quark-antiquark pairs. Collectively, quarks and gluons are referred to as partons. In a proton-proton collision, typically only one parton of each proton undergoes a hard scattering – referred to as single-parton scattering – leaving the remainder of each proton only slightly disturbed. Here, we report the study of double- and triple-parton scatterings through the simultaneous production of three J/ψ mesons, which consist of a charm quark-antiquark pair, in proton-proton collisions recorded with the CMS experiment at the Large Hadron Collider. We observed this process – reconstructed through the decays of J/ψ mesons into pairs of oppositely charged muons – with a statistical significance above five standard deviations. We measured the inclusive fiducial cross-section to be 272+141−104(stat)±17(syst)fb, and compared it to theoretical expectations for triple-J/ψ meson production in single-, double- and triple-parton scattering scenarios. Assuming factorization of multiple hard-scattering probabilities in terms of single-parton scattering cross-sections, double- and triple-parton scattering are the dominant contributions for the measured process.SCOAP3.Change history: 27 February 2023A Correction to this paper has been published: https://doi.org/10.1038/s41567-023-01992-