Shell Composition Research Articles

The effect of raw material composition of mixed carbonized canary shell and coal bio briquettes on caloric value

The fuel consumption rate rises and is expected to increase continuously, causing fuel supplies to be depleted and this condition forces the community to find alternative sources of fuel such as bio-briquettes. The waste of canary shells is widespread in Indonesia and can be used as an alternative energy source of bio-briquette making. There is a need for study on the influence of raw materials bio-briquette mixture of coal and canary shells against the value of calories produced. Bio-briquette making in this study have been done using canary shell and coal with a composition: (250 gr coal/canary shell: 12.5 tapioca starch: 50 ml water). Before briquette making, the canary shell samples are pirolysed and a grain-size reduction is performed on both of coal and canary shells. Canary shell and coal bio-briquettes are made with four variations (types). The types of bio briquette are: type I of bio-briquette with a composition of 250 gr (coal) + 12.5 gr (tapioca starch) + 50 ml (water). Type II of bio-briquette with a composition of 250 gr (canary shell) + 12.5 gr (tapioca starch) + 50 ml (water). Type III of bio-briquette with a composition of 62.5 gr canary shell + 62.5 gr coal + 12.5 gr (tapioca starch) + 50 ml (water). Bio-briquette type IV consist of 93.75 gr (canary shell) + 31.25 (coal) + 12.5 gr (tapioca starch) + 50 ml (water). After preparation, all bio briquettes are analyzed to determine the caloric value. The results of the study shows bio-briquette type I has a caloric value of 5,539 kcal/g, bio-briquette type II produces the highest calorie value of 6,354 kcal/g, and bio-briquette type III is 6,020 kcal/g. Further more bio-briquette Type IV indicate caloric value of 6,096 kcal/g. Bio-briquette type IV is the most recommended in the utilization because of the goal of this study is to use canary shell as an alternative fuel.

Briquettes from Biomass Waste

This research made three kinds of briquettes from various biomass waste, including alaban wood charcoal and rubber seed shells mixed with coal bottom ash and coal fly ash. The purpose of the study was to obtain the characteristics and quality of briquette combustion. Making briquettes is by drying, grinding, and sifting raw materials then mixed with adhesive, printing and drying. Briquettes were made with variations in composition and pressure and the particle size of the material passing through the 50 and 250 mesh sieves. Briquettes produced from alaban wood charcoal and coal bottom ash, or fly ash, obtained more bottom ash or fly ash composition characteristics. The moisture content and calorific value would be lower while the ash content was higher. While the initial ignition time, the combustion duration is getting longer, but the burning rate would decrease. Briquettes made from rubber seed shells and coal bottom ash obtained variations in composition and pressure that affect the characteristics and quality of combustion. The higher the rubber seed shell composition and pressure, the lower the water and ash content, but the calorific value increased.

Insight into multilayered alginate/chitosan microparticles for oral administration of large cranberry fruit extract

• Up to 7 layers (CHIT and ALG mv ) shell were built on the CFE-loaded ALG-based cores. • The shell was a non-lamellar, interpenetrating network of oppositely charged polysaccharides. • The mechanical resistance depends on the type of ALG used as the core material and the shell structure. • The three-layered microcapsules showed the best performance in the in vitro release study. • The applicability of the studied particles could be controlled by their core and shell structure. We present a series of multilayered alginate/chitosan microparticles fabricated via combining ionic gelation with the layer-by-layer (LbL) approach to improve oral administration of large cranberry fruit extract (CFE). Sodium alginate of low (ALG lv ) or medium (ALG mv ) viscosity was used as a core polymer, and chitosan (CHIT) and ALG mv layers were alternately assembled to form up to seven layers’ coating. Microparticles size ranged between 640 and 1120 μm, and their morphology, moisture content, and structural integrity were affected mainly by the outermost layer’s composition. Both the microgel core and shell composition of these microparticles influenced the mechanical properties determined by the parallel plates compression test. Microparticles exhibited good CFE entrapment efficiency (E.E. > 55%) and favorable release profiles in the simulated gastro-intestine environment, well described by the hybrid model of the release kinetics. Our results evidence that polysaccharide-inspired microparticles are good platforms for enhancing the oral bioavailability of poorly water-soluble therapeutic agents.

Bioactive Poly(lactic acid)-Cocoa Bean Shell Composites for Biomaterial Formulation: Preparation and Preliminary In Vitro Characterization.

The unique lignocellulosic and solvent-extractive chemical constituents of most natural fibers are rich in natural polymers and bioactive molecules that can be exploited for biomaterial formulation. However, although natural fibers’ main constituents have been already incorporated as material reinforcement and improve surface bioactivity of polymeric materials, the use of the whole natural fibers as bioactive fillers remains largely unexplored. Thus, we put forward the formulation of natural fiber filling and functionalization of biomaterials by studying the chemical composition of cocoa bean shells (CBS) and proposing the fabrication and characterization of polylactic acid (PLA) and CBS-based composite by solvent-casting. As was expected from previous studies of agro-industrial wastes, the main components of CBS were to cellulose (42.23 wt.%), lignin (22.68 wt.%), hemicellulose (14.73 wt.%), and solvent extractives (14.42 wt.%). Structural analysis (FTIR) confirms the absence of covalent bonding between materials. Thermal degradation profiles (DSC and TGA) showed similar mass losses and thermal-reaction profiles for lignocellulosic-fibers-based composites. The mechanical behavior of the PLA/CBS composite shows a stiffer material behavior than the pristine material. The cell viability of Vero cells in the presence of the composites was above 94%, and the hemolytic tendency was below 5%, while platelet aggregation increased up to 40%. Antioxidant activity was confirmed with comparable 2,2-diphe-277 nyl-1-picryl-hydrazyl-hydrate (DPPH) free-radical scavenging than Vitamin C even for PLA/CBS composite. Therefore, the present study elucidates the significant promise of CBS for bioactive functionalization in biomaterial-engineering, as the tested composite exhibited high biocompatibility and strong antioxidant activity and might induce angiogenic factors’ release. Moreover, we present an eco-friendly alternative to taking advantage of chocolate-industry by-products.

Positive effects of PVP in MIC: Preparation and characterization of Al-Core heterojunction fibers

The core-shell metastable intermolecular composites (MIC) have attracted much attention in the past few years due to their unique properties. Here, the preparation of Al-Core heterojunction fibers using PVP as a template is proposed. The nano-Al was directly added to the precursor solution of cupric acetate monohydrate (CAM)/Polyvinylpyrrolidone (PVP), and the initial Al@CAM/PVP fibers were obtained via electrospinning. The core-shell MIC fibers are then obtained by calcining the initial fibers. The morphology, structure, and composition of Al-core MIC fibers were characterized, that the energetic fibers calcined at 300 °C, 350 °C, and 400 °C have a core-shell structure with shell compositions CuxO and PVP, CuxO and CuO, respectively. The energy release characteristics of Al-core MIC were investigated, and preliminary ignition tests were performed using an ignition temperature measuring instrument and a pulsed laser. The energetic fibers calcined at 300 °C exhibited unique properties. The decomposition of PVP in the shell layer promoted exotherm, and a low-temperature exothermic peak was shown at 372–458 °C. Lower ignition temperatures and higher flame heights were observed in the combustion tests than calcination at 350 °C and 400 °C. An unexpected result was that PVP can play a positive role in Al/CuO nanothermites. Simultaneously, this preparation method provided an idea for the integrated preparation of core-shell Al-Core MIC fibers and tuning the properties of MIC.

Rapid and Application-Tailored Assessment Tool for Biogenic Powders from Crustacean Shell Waste: Fourier Transform-Infrared Spectroscopy Complemented with X-ray Diffraction, Scanning Electron Microscopy, and Nuclear Magnetic Resonance Spectroscopy.

Due to their chemical composition, richness in calcium carbonate, chitin, proteins, and pigments, and nanoporous structure, crustacean shell waste shows great potential for a wide variety of applications. Large quantities of waste shells are produced annually, meaning that they can be considered a renewable source of ecofriendly biogenic materials, which can be turned into value-added byproducts. In this paper, an IR-based technique is developed to differentiate various biogenic powders originated from crude or food-processed crustacean shells. The validity of the method is supported by cross-checking with XRD, NMR, and SEM–EDX analyses. Our goal was to determine changes in properties of waste crab shells after the two most common treatments, deproteinization and milling. We discovered that deproteinization with NaOH could be tracked from the IR absorbance intensity ratio of the υ(CH2,3) and υasym(CO32–) bands while milling time less influenced this ratio but induced changes in powder particle size distribution and morphology. The relative organic/inorganic ratio was different for different colored shells. Unexpectedly, waste shells stored for an average of 6 months or more were found to contain hydrated calcium carbonate (monohydrocalcite), which was absent in equivalent fresh shell composition. Deproteinization caused changes in mechanical properties of shells, making them more brittle, which resulted in a larger fraction of fine particles after powdering.

Magnetic cluster-encapsulated polymer dimers with controlled surface property

This work reports the fabrication of magnetic polymer dimers with controlled surface anisotropy. The fabrication process involves the preparation of magnetite (Fe3O4) magnetic clusters with strong magnetism, followed by their surface modification, dispersion polymerization while using them as seeds, multilayer shell formation via layer-by-layer deposition, and polymer core swelling. The interplay between the swelling and multilayer shells generates pressure inside the multilayer-deposited, magnetic polystyrene (PS) spheres, forming structurally anisotropic dimers with single PS protrusions anchored on the multilayer surfaces within minutes. The use of titania precursor and different swelling agents, along with the change in the composition of the multilayer shell, enables the introduction of different surface anisotropies, such as the surface-charge anisotropy, anisotropic hydrophilicity/hydrophobicity, and material composition anisotropy, to the dimers. The strong magnetic response of the dimers, attributed to the magnetic cluster seeds, in combination with the surface-charge and material composition anisotropies allows a rapid magnetic recovery and an excellent reusability, enabling their application to 20-cycled reduction of 4-nitrophenol (4-NP) and methylene blue (MB) without loss of catalytic activity. Furthermore, the anisotropic hydrophilicity/hydrophobicity makes the dimers potentially useful as solid surfactant to stabilize immiscible oil–water mixture.

Al3+ solvation in solutions of aluminum nitrate in a protic ionic liquid: Nuclear magnetic resonance verification of the solvation shell composition.

The closest environment of Al3+ cations was analyzed in detail in solutions of aluminum nitrate in the prototypical protic ionic liquid ethyl ammonium nitrate (EAN) using 1 H and 14 N nuclear magnetic resonance (NMR) spectra. For Al (NO3 )3 -EAN mixtures with different water content, a quantitative analysis of the integral intensities of the 1 H and 14 N signals was carried out and the composition of the first solvation shell of the aluminum cation was refined.

Air pore structure, strength and frost resistance of air-entrained mortar with different dosage of nano-SiO2 hydrosol

The use of nano-SiO2 in concrete has attracted intense attention recently due to its notable improvement in mechanical properties as well as consumption of industrial by-product to enhance the life cycle sustainability. However, the effect of nano-SiO2 on the air pore structure and properties of air entrained cement-based materials is almost not involved in former studies. In this paper, the influence of nano-SiO2 hydrosol (NSH) on the air pore structure, strength and frost resistance of air-entrained mortar was reported. Two typical air entrained agents (AEAs) were utilized to prepare air-entrained mortar with the targeted air content of fresh mortar at the same level. The effects of the addition of NSH on air pore structure, hydration heat release and frost resistance of air-entrained mortar were investigated. Scanning Electron Microscopy (SEM) and Energy Dispersive X-Ray Spectroscopy (EDS) were used to analyze the mechanism of NSH on entrained air bubbles and pores. Results suggest that the incorporation of NSH can affect entrained air bubble behavior, influence the pore size distribution and densify the hydration products of the air pore wall, thereby effecting the mechanical properties and frost resistance of air-entrained mortar. SEM and EDS data proved differences in chemical composition of air bubble shell entrained by two types of AEAs. The differences resulted in diverse degree of NSH affected air-entrained mortar performance. Due to the effect of early accelerated heat release of cement on the stability bubbles and excessive mortar consistency on the retention of coarse air bubble, it is not recommended to add too much NSH in order to optimize the air pore structure and frost resistance of air-entrained mortar. This study deepens our understanding into the fundamental mechanism of NSH in air-entrained mortar, which also prompts its application to create a sustainable built environment.

Relationship between salinity of the liquid and shell composition on the resonance frequency of the C3F8 lipid coated microbubbles

Lipid-coated microbubbles (MBs) are used in contrast-enhanced ultrasound (CEUS) imaging and MB enhanced therapeutic ultrasound (US). Understanding the MB behavior and the influence of the surrounding medium on its response to the US is necessary to select the suitable US exposure parameters. The MB lipid coating is often charged, however the influence of the ions in the medium on MB behavior is not fully understood. In this work, the influence of the medium salinity on the pressure-dependent MB behavior is investigated for the first time. MBs of different lipid shell compositions are size isolated to achieve the same size distribution. The MBs linear and pressure-dependent attenuation are measured in deionized water, PBS 1×, PBS 2×, and PBS 10× using a system of aligned PVDF 100% bandwidth transducers with a center frequency of 10 MHz and exposures with peak to peak pressure range of 3–140 kPa. With increasing salinity, the linear resonance frequency decreases up to 50% for conventional lipid shell compositions, and the pressure dependence of the resonance frequency is inhibited. By modifying the shell PEG ratio, the salinity effects can significantly be altered. Moreover, the nonlinear pressure-dependent resonance frequency is restored with applications to increased CEUS.

The impact of lipid shell composition of perfluorocarbon nanodroplets on size distribution and acoustic droplet vaporization and cavitation dynamics

Perfluorocarbon nanodroplets are ultrasound contrast agents that phase transition from liquid to gas when activated by lasers or insonated with a high intensity ultrasound pulse. The dynamics of perfluorocarbon nanodroplets can vary drastically depending on the nanodroplet shell and/or core composition. In this work, we investigated the role of varying lipid shell compositions and how this impacts the acoustic droplet vaporization and inertial cavitation dynamics of these nanodroplets when insonated with high intensity focused ultrasound. We also examined the role of lipid shell composition on the size distribution of these nanodroplets. Nanodroplets with a higher concentration of PEGylated lipids had larger diameters and exhibited greater variance in size distribution. Perfluorocarbon nanodroplets with a lipid shell composed of 50:50 PEGylated to non-PEGylated lipids yielded the highest intensity and duration ultrasound signal as well as the greatest pressure differential between acoustic droplet vaporization onset and inertial cavitation onset. These findings can help guide researchers to fabricate perfluorocarbon nanodroplets with optimized parameters for their specific applications, including ultrasound imaging, drug delivery, and tissue ablation.

ИЗУЧЕНИЕ РАКОВИННОГО ВЕЩЕСТВА СОВРЕМЕННЫХ И ПЛЕЙСТОЦЕНОВЫХ МОЛЛЮСКОВ РОДА DIDACNA

One of the ways to study the reactions of marine invertebrates to the external effects of changes in temperature and salinity is the biogeochemical analysis of skeletal parts, which are consistently built up during ontogenesis and record a variety of information about these changes. The most studied shells of mollusks, sea urchin shells and skeletal parts of corals. Information about the chemical composition of modern and fossil mollusk shells is widely used in solving geological and biological problems, including determining the temperature and salinity of ancient marine basins, studying the diagenesis of carbonate sediments, and the biochemical evolution of invertebrates. X-ray diffraction analysis of the shell matter of didacnae belonging to the Cardiidae showed an aragonite composition. The quantitative determination of elements in mollusk shells by microprobe analysis of spot scanning and spectrometric method is carried out. Samples were taken in successive layers of shell growth within the annual ring, and the seasonal dynamics of strontium changes were detected. For Didacna, strontium is the main element-indicator of seasonal and ontogenetic growth, is included in the crystal lattice of aragonite and forms strong compounds in the process of shell formation during the life of these bivalves. The variability of seasonal, ontogenetic, and taxonomic differences in a number of indicator elements in living and Pleistocene bivalves of the genus Didacna was studied.

Thermal stress reduces carbonate production of benthic foraminifera and changes the material properties of their shells

Abstract In shallow marine environments, benthic foraminifera are important foundation species and carbonate producers. Understanding their response to future climate is often drawn from their acclimation potential in short laboratory experiments, thereby limiting our understanding of migration, species replacement, and adaptive potential. To overcome this challenge, we examine two species of benthic foraminifera from a thermally polluted field site mimicking future warming. This site and a control station cover 13–36°C causing both warm and cold stress to the local species. Computer Tomography reveals that under heat stress, even with acclimation, Lachlanella significantly reduced its shell volume. In contrast, Pararotalia calcariformata did not reduce its shell volume but reduced the relative amount of calcite with respect to shell volume and changed its reproduction cycle from twice to once per year. Raman spectroscopy indicates that thermal conditions alter the chemical composition of the calcite shells of both species. Calcification during thermal stress creates alterations in the crystal structure that are unexpectedly more prominent under cold stress than warm stress indicating warming might positively affect the shell's protective function. Supported by previous laboratory experiments and observations from the geological record, our results provide new perspective to the effect of warming on benthic foraminifera.

Making and Characterization of Charcoal Briquettes from Palm Oil Shells and Hazelnut Shells

Research has been conducted on The Manufacture and Characterization of Charcoal Briquettes From Palm Shells And Hazelnut Shells. This study aims to determine the influence of variations in the composition of palm shells and hazelnut shells on the calorific value, moisture content, and ash content in the resulting charcoal briquettes. This study was conducted by carbonization method, mixing, printing, drying and briquette youthfulness analyzed with test parameters namely moisture content, ash content, and calorific value. The results showed a mixture of palm shell and hazelnut shell can be used as briquettes. In this study briquettes with optimal composition were a mixture of variations of palm shell and hazelnut shell 60% : 35% with a moisture content of 6.25%, ash content of 11.37% and a calorific value of 5129.45 cal / gr. Keywords : Palm Shell, Hazelnut Shell, Moisture Content, Ash Content, Calorific Value

Structural and biomechanical properties and trace elements composition of the corneoscleral eye shell in normal tension glaucoma

The results of comparative studies of the structural and biomechanical features of the corneoscleral eye shell in various clinical forms of glaucoma are presented. The article discusses how the systemic and local imbalance of trace elements that regulate collagen biosynthesis, the formation of cross-links in the connective tissue structures of the sclera, and the hydrodynamics of the intraocular fluid, affect the intraocular pressure level, and thereby the character of the development of glaucomatous lesions in normal tension glaucoma. Modern literature is shown to indicate the prospects for further research in this direction.

Acrylonitrile-Styrene-Acrylate Particles with Different Microstructure for Improving the Toughness of Poly(styrene-co-acrylonitrile) Resin

Herein, acrylonitrile-styrene-acrylate copolymer (ASA) particles with different microstructure were synthesized by emulsion polymerization and then used for toughening poly(styrene-co-acrylonitrile) (SAN) resin. The structure of ASA particles was confirmed by FTIR. TEM results demonstrated that the particles with different morphologies of multilobe shape, complete core-shell and dumbbell shape were obtained depending on the cross-linker amount. It was found that the toughening efficiency reached the highest when the ASA particles had complete core-shell structure and the shell composition was close to that of the SAN matrix. It was ascribed to the fact that the complete shell layer and similar shell composition provided sufficient interfacial adhesion and transferred stress to induce larger matrix deformation, so that the notched impact strength increased accordingly. Moreover, the notched impact strength of SAN/ASA blend was improved without significantly sacrificing tensile strength when adding 30 wt% ASA particles with the size of around 400 nm. SEM results of the impact-fractured surfaces revealed that irregular fluctuation and numerous microvoids occurred. It was deduced that the toughening mechanism was attributed to the crazings and cavitation of particles. Therefore, this study paved a way of toughening the resin by adjusting the microstructure of the particles including morphology, composition, and size.

Brachiopods from the Latham Shale Lagerstätte (Cambrian Series 2, Stage 4) and Cadiz Formation (Miaolingian, Wuliuan), California

AbstractA moderately diverse assemblage of brachiopods from the Latham Shale Lagerstätte (Cambrian Series 2, upper Stage 4) and the upper Cadiz Formation (Miaolingian, Wuliuan), California is described in detail for the first time. The fauna includes both linguliform and rhynchonelliform brachiopods—Hadrotreta primaea(Walcott, 1902),Paterina prospectensis(Walcott, 1884),Dictyonina pannula(White, 1874), andMickwitzia occidensWalcott, 1908; andNisusia fulleriMount, 1981 andWimanella highlandensis(Walcott, 1886), respectively—together with olenellid trilobites and hyolithids. The fauna differs from other Cambrian Konservat-Lagerstätten (notably Cambrian Series 2 Chengjiang and Guanshan Lagerstätten, eastern Yunnan) in that the brachiopod shell valves in many cases are still preserved with their original mineralization. Moreover, the excellently preserved shale-hosted valves even include cases with exquisite epithelial cell molds, otherwise only seen in acid-etched material from carbonate rocks. The pitted ornamentation inD. pannulaclosely resembles that described from Ordovician linguliforms. The unusual preservation ofN. fulleriprovides important clues for ancestral composition of the brachiopod shell. The two articulated rhynchonelliform species probably represent the oldest records of this group from the west Laurentia. The fauna could also represent the earliest onset of the transition from the Cambrian Evolutionary Fauna (CEF) to the Paleozoic Evolutionary Fauna (PEF).

Asymmetric polymersomes, from the formation of asymmetric membranes to the application on drug delivery

Nano drug delivery systems have attracted researchers' growing attention and are gradually emerging into the public views. More and more nano-formulations are being approved for marketing or clinical use, representing the field's booming development. Copolymer self-assembly systems such as micelles, nanoparticles, polymersomes occupy a prominent position in the field of nano-drug delivery carriers. Among them, polymersomes, unlike micelles or nanoparticles, resemble liposomes' structure and possess large internal hollow hydrophilic reservoirs, allowing them to carry hydrophilic drugs. Nevertheless, their insufficient drug loading efficiency and unruly self-assembly morphology have somewhat constrained their applications. Especially for the delivery of biomacromolecule such as peptides, the encapsulation efficiency is always considered to be a formidable obstacle, even if the enormous hydrophilic core would render the polymersomes to have considerable potential in this regard. Reassuringly, the emergence of asymmetric polymersomes holds the prospect of solving this problem. With the development of synthetic technology and a deeper understanding of the self-assembly process, the asymmetric polymersomes which are with different inner and outer shell composition have been gradually recognized by researchers. It has made possible elevated drug loading, more controllable assembly processes and release performance. The internal hydrophilic blocks different from the outer shell could be engineered to have a more remarkable affinity to the cargos or could contain a non-watery aqueous phase to enable the thermodynamically preferred encapsulation of cargos, which would allow for a substantial improvement in drug encapsulation efficiency compared to the conventional approach. In this paper, we aim to deepen the understanding to asymmetric polymersomes and lay the foundation for the development of this field by describing four main elements: the mechanism of their preparation and asymmetric membrane formation process, the characterization of asymmetric membranes, the efficient drug loading, and the special stimulus-responsive release mechanism.

Capsules with polyurea shells and ionic liquid cores for CO2 capture

AbstractMany ionic liquids (ILs) have good solubilities of CO2 but the high viscosity of ILs makes them cumbersome and kinetically limits gas uptake. Encapsulation of ILs is an effective approach to overcoming these limitations. In capsules with a core of IL, the chemical composition of the shell impacts performance. Here, we report the preparation of capsules with a core of the IL [Bmim][PF6] and polymer composite shell, then evaluate how the identity of the polymer impacts CO2 uptake. IL‐in‐oil Pickering emulsions stabilized by nanosheets are used, with capsules formed by interfacial polymerization between different diamines and diisocyanates (e.g., shells are polyurea and nanosheets). The capsules contain 60–80 wt% IL and the composition was verified using Fourier transform infrared spectroscopy. Optical microscopy, scanning electron microscopy, and particle sizing data showed spherical, discrete capsules with 50–125 μm in diameter. All capsules are stable up to 250°C. Brunauer–Emmett–Teller analysis of CO2 gas uptake data showed that different polymer compositions led to different CO2 uptake properties, with capacity ranging from 0.065 to 0.025 moles of CO2/kg sorbent at 760 torr and 20°C. This work demonstrates that the polymer identity of the shell impacts gas uptake properties and supports that shell composition can tailor performance.

An Evaluation of a Systematic Series of Cobalt-Free Ni-Rich Core-Shell Materials as Positive Electrode Materials for Li-Ion Batteries

A wide range of Co-free Ni-rich core–shell precursors with different core/shell compositions, core sizes and shell thicknesses heated at various temperatures were evaluated in this work. In all cases, the shell phase had a larger Mn content than the core phase. The heating temperature of the precursor/lithium hydroxide mixture during synthesis must be carefully selected. Core–shell materials made at insufficient temperature have low specific capacity due to low crystallinity and a high percentage of Ni atoms in the Li layer. Materials made at excessive temperature show interdiffusion between the shell and core compositions leading to poor capacity retention and poor safety performance. When the heating temperature is selected appropriately, materials which retain the core–shell structure after synthesis can be made. Two of these materials show excellent specific capacity, capacity retention and safety performance. Accelerating rate calorimetry experiments show that charged core–shell materials with a thick and Mn-rich shell have the least reactivity with electrolyte at elevated temperatures, suggesting such materials will lead to the safest Li-ion cells.