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All-solid-state batteries are intensively investigated, although their performance is not yet satisfactory for large-scale applications. In this context, the combination of Li 10 GeP 2 S 12 solid electrolyte and LiNi 1-x-y Co x Mn y O 2 positive electrode active materials is considered promising despite the yet unsatisfactory battery performance induced by the thermodynamically unstable electrode|electrolyte interface. Here, we report electrochemical and spectrometric studies to monitor the interface evolution during cycling and understand the reactivity and degradation kinetics. We found that the Wagner-type model for diffusion-controlled reactions describes the degradation kinetics very well, suggesting that electronic transport limits the growth of the degradation layer formed at the electrode|electrolyte interface. Furthermore, we demonstrate that the rate of interfacial degradation increases with the state of charge and the presence of two oxidation mechanisms at medium (3.7 V vs . Li + /Li < E  < 4.2 V vs . Li + /Li) and high ( E  ≥ 4.2 V vs . Li + /Li) potentials. A high state of charge (>80%) triggers the structural instability and oxygen release at the positive electrode and leads to more severe degradation. Fundamental investigations at the electrode/electrolyte interface are essential for developing high-energy batteries. Here, the authors investigate the degradation mechanisms at the LGPS/NCM622 interface providing a quantitative model to interpret the interfacial resistance growth.

This article presents a new analytical methodology to analyze large (hundreds of µm) battery electrode microstructures by mapping the spatial distribution of the main phases (e.g., active material and carbon‐binder domain) and degradation products (solid‐ or cathode‐electrolyte interphase) formed during cycling. The methodology can be used for a better understanding of the relationships between electrode architecture and degradation, paving the way toward the analysis of interphases spatial distribution and their correlations to the electrode formulation, microstructure, and cycling conditions. This work is based on time‐of‐flight secondary ion mass spectrometry (ToF‐SIMS), and focuses on analyzing large 2D electrode cross‐sections at both the microstructure and single particle/agglomerate level. It also shows that this analysis can be expanded to 3D electrode microstructures when combining ToF‐SIMS and devoted machine learning procedures, which can be of particular interest to the 3D electrochemical modeling community. Time‐of‐flight secondary ion mass spectrometry imaging allows the characterization of 2D electrode microstructures of state‐of‐the‐art cathodes (NMC‐based) and anodes (graphite‐silicon‐based) of lithium‐ion batteries. The electrode main phase, such as active material, as well as the degradation products (solid‐ and cathode‐electrolyte interphase) formed during battery cycling can be mapped chemically and spatially. Combination with machine learning procedures, namely SliceGAN, allows the reconstruction of statistically representative 3D microstructures.

The solid electrolyte interphase (SEI) formation on hard carbon (HC), as one of the most widely used anode materials in sodium (Na)‐ion batteries, is still not fully understood compared to the SEI formation on anodes used in lithium (Li)‐ion batteries, in terms of passivation properties and stability, which strongly depends on various factors such as experimental parameters and the electrolyte composition. Herein, we report the localized formation of SEI microspots on HC using cyclic voltammetry in combination with scanning electrochemical cell microscopy (SECCM) in non‐aqueous ether‐ and carbonate‐based electrolytes. Using the same instrumental setup for SECCM and for atomic force microscopy (AFM), the locally formed SEI spots could be directly characterized with respect to the morphology, height, passivation and nanomechanical properties in dependence of the experimental deposition parameters such as scan rate and cycling number. In addition, time‐of‐flight secondary ion mass spectrometry (ToF‐SIMS) in combination with AFM revealed the chemical composition of the SEI layer by recording spatially resolved 3D mass maps of the SEI spots. This combination of high‐resolution microscopic and spectrometric methods provides new insights into the dynamics of SEI formation as a function of the electrolyte and the experimental parameters. The local formation of the solid electrolyte interphase (SEI) on hard carbon is demonstrated by scanning electrochemical cell microscopy (SECCM). The formation of SEI microspots allows the direct study of the effects of the electrolyte composition and experimental parameters on the morphology, height, passivation and nanomechanical properties of the SEI using an SPM instrument, capable of switching the scan head from SECCM to AFM.

Polyolefin catalysts are characterized by their hierarchically complex nature, which complicates studies on the interplay between the catalyst and formed polymer phases. Here, the missing link in the morphology gap between planar model systems and industrially relevant spherical catalyst particles is introduced through the use of a spherical cap Ziegler-type catalyst model system for the polymerization of ethylene. More specifically, a moisture-stable LaOCl framework with enhanced imaging contrast has been designed to support the TiCl 4 pre-active site, which could mimic the behaviour of the highly hygroscopic and industrially used MgCl 2 framework. As a function of polymerization time, the fragmentation behaviour of the LaOCl framework changed from a mixture of the shrinking core (i.e., peeling off small polyethylene fragments at the surface) and continuous bisection (i.e., internal cleavage of the framework) into dominantly a continuous bisection model, which is linked to the evolution of the estimated polyethylene volume and the fraction of crystalline polyethylene formed. The combination of the spherical cap model system and the used advanced micro-spectroscopy toolbox, opens the route for high-throughput screening of catalyst functions with industrially relevant morphologies on the nano-scale. Ziegler-type polyolefin catalysts have proven to be hard to characterize. Here the authors present a model system consisting of patterned LaOCl spherical caps, simulating bulk particles while facilitating the use of micro(-spectro)scopic characterization techniques specifically aimed at surfaces.

Low‐fouling materials are often generated by surface zwitterionization with polymers. In this context, poly‐N‐oxides have recently attracted considerable attention as biomimetic stealth coatings with low protein adsorption. Herein, this study reports that poly‐N‐oxides can be grafted from plasma‐activated plastic base materials. The resulting hydrophilic surfaces have low‐fouling properties in bacterial suspensions and suppress the formation of biofilms. Moreover, efficient antibacterial activity against Gram‐negative and Gram‐positive bacteria caused by release of reactive oxygen species is observed. The latter effect is specific for polymeric N‐oxides and is most likely triggered by a reductive activation of the N‐oxide functionality in the presence of bacteria. In contrast to other zwitterionic polymers, N‐oxides combine thus low‐fouling (stealth) properties with antibacterial activity. The bioactive N‐oxide groups can be regenerated after use by common oxidative disinfectants. Poly‐N‐oxides are thus attractive antibacterial coatings for many base materials with a unique combined mechanism of action. Poly‐N‐oxides can be grafted from plasma‐activated plastic base materials. The resulting hydrophilic surfaces have low‐fouling properties in bacterial suspensions and suppress the formation of biofilms. Moreover, efficient antibacterial activity against Gram‐negative and Gram‐positive bacteria have been observed. The latter effect is caused by release of reactive oxygen species and is specific for polymeric N‐oxides. In contrast to other zwitterionic polymers, N‐oxides combine thus low‐fouling (stealth) properties with antibacterial activity.

The development and characterization of biomaterials for bone replacement in case of large defects in preconditioned bone (e.g., osteoporosis) require close cooperation of various disciplines. Of particular interest are effects observed in vitro at the cellular level and their in vivo representation in animal experiments. In the present case, the material-based alteration of the ratio of osteoblasts to osteoclasts in vitro in the context of their co-cultivation was examined and showed equivalence to the material-based stimulation of bone regeneration in a bone defect of osteoporotic rats. Gelatin-modified calcium/strontium phosphates with a Ca:Sr ratio in their precipitation solutions of 5:5 and 3:7 caused a pro-osteogenic reaction on both levels in vitro and in vivo. Stimulation of osteoblasts and inhibition of osteoclast activity were proven during culture on materials with higher strontium content. The same material caused a decrease in osteoclast activity in vitro. In vivo, a positive effect of the material with increased strontium content was observed by immunohistochemistry, e.g., by significantly increased bone volume to tissue volume ratio, increased bone morphogenetic protein-2 (BMP2) expression, and significantly reduced receptor activator of nuclear factor kappa-B ligand (RANKL)/osteoprotegerin (OPG) ratio. In addition, material degradation and bone regeneration were examined after 6 weeks using stage scans with ToF-SIMS and µ-CT imaging. The remaining material in the defects and strontium signals, which originate from areas exceeding the defect area, indicate the incorporation of strontium ions into the surrounding mineralized tissue. Thus, the material inherent properties (release of biologically active ions, solubility and degradability, mechanical strength) directly influenced the cellular reaction in vitro and also bone regeneration in vivo. Based on this, in the future, materials might be synthesized and specifically adapted to patient-specific needs and their bone status.

Background Accumulation of malignant plasma cells in the bone marrow causes lytic bone lesions in 80% of multiple myeloma patients. Frequently fracturing, they are challenging to treat surgically. Myeloma cells surviving treatment in the presumably protective environment of bone lesions impede their healing by continued impact on bone turnover and can explain regular progression of patients without detectable minimal residual disease (MRD). Locally applicable biomaterials could stabilize and foster healing of bone defects, simultaneously delivering anti-cancer compounds at systemically intolerable concentrations, overcoming drug resistance. Methods We developed silica-collagen xerogels (sicXer) and bortezomib-releasing silica-collagen xerogels (boXer) for local treatment of osteolytic bone disease and MRD. In vitro and in vivo (tissue sections) release of bortezomib was assessed by ultrahigh-performance liquid chromatography coupled to tandem mass spectrometry (UPLC-MS/MS) and time-of-flight secondary ion mass spectrometry (ToF-SIMS). Material impact on bone formation was assessed in vitro regarding osteoclast/osteoblast numbers and activity. In vivo, drilling defects in a rat- and the 5T33-myeloma mouse model were treated by both materials and assessed by immunohistochemistry, UPLC-MS/MS, µCT, and ToF-SIMS. The material’s anti-myeloma activity was assessed using ten human myeloma cell lines (HMCLs) and eight primary myeloma cell samples including four patients refractory to systemic bortezomib treatment. Results sicXer and boXer show primary stability comparable to trabecular bone. Granule size and preparation method tailor degradation as indicated by release of the xerogel components (silica and collagen) and bortezomib into culture medium. In vitro , both materials reduce osteoclast activity and do not negatively interfere with osteoblast differentiation and function. The presumed resulting net bone formation with maintained basic remodeling properties was validated in vivo in a rat bone defect model, showing significantly enhanced bone formation for boXer compared to non-treated defects. Both materials induce myeloma cell apoptosis in all HMCLs and primary myeloma cell samples. In the 5T33-myeloma mouse model, both materials stabilized drilling defects and locally controlled malignant plasma cell growth. Conclusions The combination of stabilization of fracture-prone lesions, stimulation of bone healing, and anti-tumor effect suggest clinical testing of sicXer and boXer as part of a combined systemic/local treatment strategy in multiple myeloma and non-malignant diseases.

In this study, the in vitro and in vivo bone formation behavior of mesoporous bioactive glass (MBG) particles incorporated in a pasty strontium-containing calcium phosphate bone cement (pS100G10) was studied in a metaphyseal fracture-defect model in ovariectomized rats and compared to a plain pasty strontium-containing calcium phosphate bone cement (pS100) and control (empty defect) group, respectively. In vitro testing showed good cytocompatibility on human preosteoblasts and ongoing dissolution of the MBG component. Neither the released strontium nor the BMG particles from the pS100G10 had a negative influence on cell viability. Forty-five female Sprague–Dawley rats were randomly assigned to three different treatment groups: (1) pS100 (n = 15), (2) pS100G10 (n = 15), and (3) empty defect (n = 15). Twelve weeks after bilateral ovariectomy and multi-deficient diet, a 4 mm wedge-shaped fracture-defect was created at the metaphyseal area of the left femur in all animals. The originated fracture-defect was substituted with pS100 or pS100G10 or left empty. After six weeks, histomorphometrical analysis revealed a statistically significant higher bone volume/tissue volume ratio in the pS100G10 group compared to the pS100 (p = 0.03) and empty defect groups (p = 0.0001), indicating enhanced osteoconductivity with the incorporation of MBG. Immunohistochemistry revealed a significant decrease in the RANKL/OPG ratio for pS100 (p = 0.004) and pS100G10 (p = 0.003) compared to the empty defect group. pS100G10 showed a statistically higher expression of BMP-2. In addition, a statistically significant higher gene expression of alkaline phosphatase, osteoprotegerin, collagen1a1, collagen10a1 with a simultaneous decrease in RANKL, and carbonic anhydrase was seen in the pS100 and pS100G10 groups compared to the empty defect group. Mass spectrometric imaging by time-of-flight secondary ion mass spectrometry (ToF-SIMS) showed the release of Sr2+ ions from both pS100 and pS100G10, with a gradient into the interface region. ToF-SIMS imaging also revealed that resorption of the MBG particles allowed for new bone formation in cement pores. In summary, the current work shows better bone formation of the injectable pasty strontium-containing calcium phosphate bone cement with incorporated mesoporous bioactive glass compared to the bioactive-free bone cement and empty defects and can be considered for clinical application for osteopenic fracture defects in the future.