Discover the most talked about and latest scientific content & concepts.

Concept: Nickel-cadmium battery


Improving one property without sacrificing others is challenging for lithium-ion batteries due to the trade-off nature among key parameters. Here we report a chemical vapor deposition process to grow a graphene-silica assembly, called a graphene ball. Its hierarchical three-dimensional structure with the silicon oxide nanoparticle center allows even 1 wt% graphene ball to be uniformly coated onto a nickel-rich layered cathode via scalable Nobilta milling. The graphene-ball coating improves cycle life and fast charging capability by suppressing detrimental side reactions and providing efficient conductive pathways. The graphene ball itself also serves as an anode material with a high specific capacity of 716.2 mAh g(-1). A full-cell incorporating graphene balls increases the volumetric energy density by 27.6% compared to a control cell without graphene balls, showing the possibility of achieving 800 Wh L(-1) in a commercial cell setting, along with a high cyclability of 78.6% capacity retention after 500 cycles at 5C and 60 °C.

Concepts: Density, Battery, Rechargeable battery, Lithium-ion battery, Lithium, Nanowire battery, Energy density, Nickel-cadmium battery


Power supply represents a critical challenge in the development of body-integrated electronic technologies. Although recent research establishes an impressive variety of options in energy storage (batteries and supercapacitors) and generation (triboelectric, piezoelectric, thermoelectric, and photovoltaic devices), the modest electrical performance and/or the absence of soft, biocompatible mechanical properties limit their practical use. The results presented here form the basis of soft, skin-compatible means for efficient photovoltaic generation and high-capacity storage of electrical power using dual-junction, compound semiconductor solar cells and chip-scale, rechargeable lithium-ion batteries, respectively. Miniaturized components, deformable interconnects, optimized array layouts, and dual-composition elastomer substrates, superstrates, and encapsulation layers represent key features. Systematic studies of the materials and mechanics identify optimized designs, including unusual configurations that exploit a folded, multilayer construct to improve the functional density without adversely affecting the soft, stretchable characteristics. System-level examples exploit such technologies in fully wireless sensors for precision skin thermography, with capabilities in continuous data logging and local processing, validated through demonstrations on volunteer subjects in various realistic scenarios.

Concepts: Electricity, Solar cell, Photovoltaics, Rechargeable battery, Capacitor, Lithium-ion battery, Solar energy, Nickel-cadmium battery


An important trend in electronics involves the development of materials, mechanical designs and manufacturing strategies that enable the use of unconventional substrates, such as polymer films, metal foils, paper sheets or rubber slabs. The last possibility is particularly challenging because the systems must accommodate not only bending but also stretching. Although several approaches are available for the electronics, a persistent difficulty is in power supplies that have similar mechanical properties, to allow their co-integration with the electronics. Here we introduce a set of materials and design concepts for a rechargeable lithium ion battery technology that exploits thin, low modulus silicone elastomers as substrates, with a segmented design in the active materials, and unusual ‘self-similar’ interconnect structures between them. The result enables reversible levels of stretchability up to 300%, while maintaining capacity densities of ~1.1 mAh cm(-2). Stretchable wireless power transmission systems provide the means to charge these types of batteries, without direct physical contact.

Concepts: Polymer, Battery, Rechargeable battery, Lithium-ion battery, Lithium, Nickel-cadmium battery, Electric power transmission, Wireless energy transfer


A Si/graphene composite is drop-casted on an ultrathin-graphite foam (UGF) with three dimensional conductive network. The Si/graphene/UGF composite presents excellent stability and relatively high overall capacity when tested as an anode for rechargeable lithium ion batteries.

Concepts: Rechargeable battery, Lithium-ion battery, Lithium, Lithium battery, Lithium-ion polymer battery, Nanowire battery, Nickel-metal hydride battery, Nickel-cadmium battery


Down to the wire: Three-dimensional interconnected Si-based nanowires are produced through the combination of thermal decomposition of SiO and a metal-catalyzed nanowire growth process. This low-cost and scalable approach provides a promising candidate for high-capacity anodes in lithium-ion batteries.

Concepts: Nanowire, Rechargeable battery, Lithium-ion battery, Lithium-ion polymer battery, Nanowire battery, Nickel-metal hydride battery, Nickel-cadmium battery, Lithium iron phosphate battery


Spinel-type LiNi0.5Mn1.5O4 porous nanorods assembled with nanoparticles have been prepared and investigated as high-rate and long-life cathode materials for rechargeable lithium-ion batteries. One dimensional porous nanostructures of LiNi0.5Mn1.5O4 with ordered P4332 phase were obtained through solid-state Li and Ni implantation of porous Mn2O3 nanorods that resulted from thermal decomposition of the chain-like MnC2O4 precursor. The fabricated LiNi0.5Mn1.5O4 delivered specific capacities of 140 and 109 mAh g-1 at 1 C and 20 C rate, respectively. At 5 C cycling rate, a capacity retention of 91% was sustained after 500 cycles, with extremely low capacity fade (< 1%) during the initial 300 cycles. The remarkable performance was attributed to the porous 1D nanostructures that can accommodate strain relaxation by slippage at the subunits wall boundaries and provide short Li-ion diffusion distance along the confined dimension.

Concepts: Rechargeable battery, Lithium-ion battery, Lithium, Lithium-ion polymer battery, Nanowire battery, Nickel-metal hydride battery, Nickel-cadmium battery, Lithium iron phosphate battery


To reduce cost and secondary pollution of spent lithium ion battery (LIB) recycling caused by complicated separation and purification, a novel simplified recycling process is investigated in this paper. Removal of magnesium is a common issue in hydrometallurgy process. Considering magnesium as an important additive in LIB modification, tolerant level of magnesium in leachate is explored as well. Based on the novel recycling technology, Li[(Ni(1/3)Co(1/3)Mn(1/3))(1-x)Mg(x)]O(2) (0≤x≤0.05) cathode materials are achieved from spent LIB. Tests of XRD, SEM, TG-DTA and so on are carried out to evaluate material properties. Electrochemical test shows an initial charge and discharge capacity of the regenerated LiNi(1/3)Co(1/3)Mn(1/3)O(2) to be 175.4mAhg(-1) and 152.7mAhg(-1) (2.7-4.3V, 0.2C), respectively. The capacity remains 94% of the original value after 50 cycles (2.7-4.3V, 1C). Results indicate that presence of magnesium up to x=0.01 has no significant impact on overall performance of Li[(Ni(1/3)Co(1/3)Mn(1/3))(1-x)Mg(x)]O(2). As a result, magnesium level as high as 360mgL(-1) in leachate remains tolerable. Compared with conventional limitation of magnesium content, the elimination level of magnesium exceeded general impurity-removal requirement.

Concepts: Battery, Rechargeable battery, Recyclable materials, Lithium-ion battery, Lithium, Lithium battery, Lithium-ion polymer battery, Nickel-cadmium battery


TiO2/Graphene composites have been well studied as a solar light photocatalysts and electrode materials for lithium-ion batteries (LIBs). Recent reports have shown that ultralight 3D-graphene aerogels (GAs) can better adsorb organic pollutants and can provide multidimensional electron transport pathways, implying a significant potential application for photocatalysis and LIBs. Here, we report a simple one-step hydrothermal method towards in-situ growth of ultradispersed mesoporous TiO2 nanocrystals with (001) facets on GAs. This method uses glucose as the dispersant and linker owing to its hierarchically porous structure and a high surface area. The TiO2/GAs reported here exhibit a highly recyclable photocatalytic activity for methyl orange pollutant and a high specific capacity in LIBs. The strong interaction between TiO2 and GAs, the facet characteristics, the high electrical conductivity, and the 3-dimensional hierarchically porous structure of these composites result in highly active photocatalysis, a high rate capability, and stable cycling.

Concepts: Rechargeable battery, Lithium-ion battery, Lithium, Lithium battery, Lithium-ion polymer battery, Photocatalysis, Electric car, Nickel-cadmium battery


This paper analyses the capacity of the rape (Brassica napus) to extract Cd and Zn from the soil and the effect of these metals on the morphometric parameters of the plant (length, weight, surface area, fractal dimension of leaves). Rape plants were mostly affected by the combined toxicity of the Cd and Zn mixture that caused a significant reduction in the rate of seed germination, the plant biomass quantity and the fractal dimension. In the case of Cd soil pollution, the bioaccumulation factor (BAF), bioaccumulation coefficient (BAC) as well as the heavy metal root-to-stalk translocation factor (TF) were determined. The results showed that B. napus had a great potential as a cadmium hyperaccumulator but not as an accumulator of Zn or Cd + Zn mixture. The efficiency of phytoextraction rape was 0.8-1.22 % for a soil heavily polluted with cadmium.

Concepts: Toxicology, Zinc, Pollution, Seed, Plant morphology, Heavy metal music, Soil contamination, Nickel-cadmium battery


Agricultural soils are likely to be polluted by both conventional and emerging contaminants at the same time. Understanding the interactions of co-existing engineered nanoparticles (ENPs) and trace-elements (a common source of abiotic stress) is critical to gain insights into the accumulation of these two groups of chemicals by plants. The objectives of this study were to determine the uptake and accumulation of co-existing ENPs and trace-elements by soybeans and to gain insights into the physiological mechanisms resulting in different plant accumulation of these materials. The combinations of three cadmium levels: 0 (control) and 0.25 and 1 mg kg-1 dry soil, and two CeO2NPs concentrations: 0 (control) and 500 mg kg-1 dry soil were investigated. Measurements of the plant biomass and physiological parameters indicated that CeO2NPs led to higher Fv/Fm ratio, suggesting that CeO2NPs enhanced the plant light energy use efficiency by photosystem II. In addition, the presence of CeO2NPs did not affect Cd accumulation in soybean, but Cd significantly increased the accumulation of Ce in plant tissues, especially in roots and older leaves. The altered Ce in-planta distribution was partially associated with the formation of root apoplastic barriers in the co-presence of Cd and CeO2NPs.

Concepts: Photosynthesis, Plant, Soybean, Root, Chlorophyll, Soil contamination, Soy milk, Nickel-cadmium battery