Fast-charging batteries typically use electrodes capable of accommodating lithium continuously by means of solid-solution transformation because they have few kinetic barriers apart from ionic diffusion. One exception is lithium titanate (Li₄Ti₅O₁₂), an anode exhibiting extraordinary rate capability apparently inconsistent with its two-phase reaction and slow Li diffusion in both phases. Through real-time tracking of Li⁺ migration using operando electron energy-loss spectroscopy, we reveal that facile transport in Li_{4+ x} Ti₅O₁₂ is enabled by kinetic pathways comprising distorted Li polyhedra in metastable intermediates along two-phase boundaries. Our work demonstrates that high-rate capability may be enabled by accessing the energy landscape above the ground state, which may have fundamentally different kinetic mechanisms from the ground-state macroscopic phases. This insight should present new opportunities in searching for high-rate electrode materials.

Li-excess cation-disordered rocksalt (DRX) oxides have shown potential as high-energy-density Li-ion cathodes. They typically exploit O redox to achieve high capacity, which can trigger oxygen loss at the surface, thereby affecting the cathode performance. Here, we elucidate the impact that the surface structural evolution has on their electrochemical properties by comparing two prototypical DRX cathodes, Li1.2Ni0.333Ti0.333Mo0.133O2 (LNTMO) and Li1.2Mn0.6Nb0.2O2 (LMNO). Both cathodes achieve high capacity, but oxygen loss leads to significant polarization for LNTMO, whereas LMNO is far less affected. We show that while metal densification at the particle surface occurs for both materials, the resulting surface structure is strikingly different. A spinel phase forms at the surface of LMNO, which effectively alleviates oxygen loss and allows fast Li transport, whereas a densified DRX forms at the LNTMO surface, which impedes Li transport and cannot mitigate oxygen loss. These findings demonstrate the importance of the surface structure of DRX cathode.

Lattice oxygen can play an intriguing role in electrochemical processes, not only maintaining structural stability, but also influencing electron and ion transport properties in high-capacity oxide cathode materials for Li-ion batteries. Here, we report the design of a gas-solid interface reaction to achieve delicate control of oxygen activity through uniformly creating oxygen vacancies without affecting structural integrity of Li-rich layered oxides. Theoretical calculations and experimental characterizations demonstrate that oxygen vacancies provide a favourable ionic diffusion environment in the bulk and significantly suppress gas release from the surface. The target material is achievable in delivering a discharge capacity as high as 301 mAh g(-1) with initial Coulombic efficiency of 93.2%. After 100 cycles, a reversible capacity of 300 mAh g(-1) still remains without any obvious decay in voltage. This study sheds light on the comprehensive design and control of oxygen activity in transition-metal-oxide systems for next-generation Li-ion batteries.

The beta chemokine known as 6-C-kine, secondary lymphoid-tissue chemokine (SLC), TCA4, or Exodus-2 (herein referred to as 6CK/SLC) can trigger rapid integrin-dependent arrest of lymphocytes rolling under physiological shear and is highly expressed by high endothelial venules, specialized vessels involved in lymphocyte homing from the blood into lymph nodes and Peyer's patches. We show that 6CK/SLC is an agonist for the lymphocyte chemoattractant receptor, CCR7 (EBI-1, BLR-2), previously described as a receptor for the related beta chemokine MIP-3beta (ELC or Exodus-3). Moreover, 6CK/SLC and MIP-3beta attract the same major populations of circulating lymphocytes, including naive and memory T cells > B cells (but not natural killer cells); desensitization to MIP-3beta inhibits lymphocyte chemotaxis to 6CK/SLC but not to the alpha chemokine SDF-1 (stromal cell-derived factor); and 6CK/SLC competes for MIP-3beta binding to resting mouse lymphocytes. The findings suggest that the majority of circulating lymphocytes respond to 6CK/SLC and MIP-3beta in large part through their common receptor CCR7 and that these molecules may be important mediators of physiological lymphocyte recirculation in vivo.

Lattice oxygen can play an intriguing role in electrochemical processes, not only maintaining structural stability, but also influencing electron and ion transport properties in high-capacity oxide cathode materials for Li-ion batteries. Here, we report the design of a gas-solid interface reaction to achieve delicate control of oxygen activity through uniformly creating oxygen vacancies without affecting structural integrity of Li-rich layered oxides. Theoretical calculations and experimental characterizations demonstrate that oxygen vacancies provide a favourable ionic diffusion environment in the bulk and significantly suppress gas release from the surface. The target material is achievable in delivering a discharge capacity as high as 301 mAh g(-1) with initial Coulombic efficiency of 93.2%. After 100 cycles, a reversible capacity of 300 mAh g(-1) still remains without any obvious decay in voltage. This study sheds light on the comprehensive design and control of oxygen activity in transition-metal-oxide systems for next-generation Li-ion batteries.

Great focus has recently been placed on anionic redox, to which high capacities of Li-rich layered oxides are attributed. With almost doubled capacity compared with state-of-the-art cathode materials, Li-rich layered oxides still fall short in other performance metrics. Among these, voltage decay upon cycling remains the most hindering obstacle, in which defect electrochemistry plays a critical role. Here, we reveal that the metastable state of cycled Li-rich layered oxide, which stems from structural defects in different dimensions, is responsible for the voltage decay. More importantly, through mild thermal energy, the metastable state can be driven to a stable state, bringing about structural and voltage recovery. However, for the classic layered oxide without reversible anionic redox, thermal energy can only introduce cation disordering, leading to performance deterioration. These insights elucidate that understanding the structure metastability and reversibility is essential for implementing design strategies to improve cycling stability for high-capacity layered oxides.

Nanoparticulate electrodes, such as Li _x FePO₄, have unique advantages over their microparticulate counterparts for the applications in Li-ion batteries because of the shortened diffusion path and access to nonequilibrium routes for fast Li incorporation, thus radically boosting power density of the electrodes. However, how Li intercalation occurs locally in a single nanoparticle of such materials remains unresolved because real-time observation at such a fine scale is still lacking. We report visualization of local Li intercalation via solid-solution transformation in individual Li _x FePO₄ nanoparticles, enabled by probing sub-angstrom changes in the lattice spacing in situ. The real-time observation reveals inhomogeneous intercalation, accompanied with an unexpected reversal of Li concentration at the nanometer scale. The origin of the reversal phenomenon is elucidated through phase-field simulations, and it is attributed to the presence of structurally different regions that have distinct chemical potential functions. The findings from this study provide a new perspective on the local intercalation dynamics in battery electrodes.

Multiple lithium-ion transport pathways and local phase changes upon lithiation in silver hollandite are revealed via in situ microscopy including electron diffraction, imaging and spectroscopy, coupled with density functional theory and phase field calculations. We report unexpected inter-nanorod lithium-ion transport, where the reaction fronts and kinetics are maintained within the neighbouring nanorod. Notably, this is the first time-resolved visualization of lithium-ion transport within and between individual nanorods, where the impact of oxygen deficiencies is delineated. Initially, fast lithium-ion transport is observed along the long axis with small net volume change, resulting in two lithiated silver hollandite phases distinguishable by orthorhombic distortion. Subsequently, a slower reaction front is observed, with formation of polyphase lithiated silver hollandite and face-centred-cubic silver metal with substantial volume expansion. These results indicate lithium-ion transport is not confined within a single nanorod and may provide a paradigm shift for one-dimensional tunnelled materials, particularly towards achieving high-rate capability.

The oxygen stacking of O3-type layered sodium transition metal oxides (O3-NaTMO2) changes dynamically upon topotactic Na extraction and reinsertion. While the phase transition from octahedral to prismatic Na coordination that occurs at intermediate desodiation by transition metal slab gliding is well understood, the structural evolution at high desodiation, crucial to achieve high reversible capacity, remains mostly uncharted. In this work, the phase transitions of O3-type layered NaTMO2 at high voltage are investigated by combining experimental and computational approaches. An OP2-type phase that consists of alternating octahedral and prismatic Na layers is directly observed by in situ X-ray diffraction and high-resolution scanning transmission electron microscopy. The origin of this peculiar phase is explained by atomic interactions involving Jahn–Teller active Fe4+ and distortion tolerant Ti4+ that stabilize the local Na environment. The path-dependent desodiation and resodiation pathways are also rationalized in this material through the different kinetics of the prismatic and octahedral layers, presenting a comprehensive picture about the structural stability of the layered materials upon Na intercalation.

Abstract Background Genetic variants in TRAF1C5 and PTPN22 genes have been shown to be significantly associated with arthritis rheumatoid in Caucasian populations. This study investigated the association between single nucleotide polymorphisms (SNPs) in TRAF1/C5 and PTPN22 genes and rheumatoid arthritis (RA) in a Han Chinese population. We genotyped SNPs rs3761847 and rs7021206 at the TRAF1/C5 locus and rs2476601 SNP in the PTPN22 gene in a Han Chinese cohort composed of 576 patients with RA and 689 controls. The concentrations of anti-cyclic citrullinated peptide antibodies (CCP) and rheumatoid factor (RF) were determined for all affected patients. The difference between the cases and the controls was compared using χ 2 analysis. Results Significant differences in SNPs rs3761847 and rs7021206 at TRAF1/C5 were observed between the case and control groups in this cohort; the allelic p-value was 0.0018 with an odds ratio of 1.28 for rs3761847 and 0.005 with an odds ratio of 1.27 for rs7021206. This significant association between rs3761847 and RA was independent of the concentrations of anti-CCP and RF. No polymorphism of rs2476601 was observed in this cohort. Conclusions We first demonstrated that genetic variants at the TRAF1/C5 locus are significantly associated with RA in Han Chinese, suggesting that TRAF1/C5 may play a role in the development of RA in this population, which expands the pathogenesis role of TRAF1/C5 in a different ethnicity.