A high-power and fast charging Li-ion battery with outstanding cycle-life

Electrochemical energy storage devices based on Li-ion cells currently power almost all electronic devices and power tools. The development of new Li-ion cell configurations by incorporating innovative functional components (electrode materials and electrolyte formulations) will allow to bring this technology beyond mobile electronics and to boost performance largely beyond the state-of-the-art. Here we demonstrate a new full Li-ion cell constituted by a high-potential cathode material, i.e. LiNi0.5Mn1.5O4, a safe nanostructured anode material, i.e. TiO2, and a composite electrolyte made by a mixture of an ionic liquid suitable for high potential applications, i.e. Pyr1,4PF6, a lithium salt, i.e. LiPF6, and standard organic carbonates. The final cell configuration is able to reversibly cycle lithium for thousands of cycles at 1000 mAg-1 and a capacity retention of 65% at cycle 2000. © 2017 The Author(s)

Nanoporous carbons from hydrothermally treated biomass as anode materials for lithium ion batteries

Biomass is transformed to carbon nanoparticles with surface-end groups called ‘hydrochar’ (HC) by an efficient and green hydrothermal carbonization (HTC) method. Three different approaches are used to introduce porosity to the HC: sole heat treatment, traditional potassium hydroxide (KOH) activation, and environmentally benign magnesium oxide (MgO) templating. All the resulting microporous materials are tested as Li-ion intercalation hosts in lithium cells by using an 1 M LiPF6 in EC/DMC electrolyte solution. They all show stable reversible capacities at elevated current rates (1C), closely comparable to the maximum theoretical capacity of graphite. Among all the materials studied, the HC-MA with a surface area of 150 m2 g1 and obtained by MgO templating of the hydrochar shows the best cycling performance in lithium cell at room temperature (307 mAh g1 at cycle 100 at 1C). The HC-600 with the highest degree of aromaticity/order, lowest content of oxygen functional groups and surface area of 250 m2 g1, obtained by heating the hydrochar at 600 C under inert atmosphere, shows the best power and overall performance with its ability to sustain high discharge/charge rates (1C, 2C, 5C, 10C, 20C). These electrochemical performances attained with materials of reasonable specific surface areas – obtained by green, low cost and practical strategies – can address the space limitations in Li-ion battery applications by improving volumetric energy densities

High performance Na0.5[Ni0.23Fe0.13Mn0.63]O2 cathode for sodium-ion battery

The synthesis of a new layered cathode material, Na0.5[Ni0.23Fe0.13Mn0.63]O2, and its characterization in terms of crystalline structure and electrochemical performance in a sodium cell, is reported. X-ray diffraction studies and high resolution SEM images reveal a well-defined P2-type layered structure, while the electrochemical tests evidence excellent characteristics in terms of high capacity, extending up to 200 mAh g-1, and cycle life, up to 70 cycles. This performance, in addition to the low cost and environmental compatibility of its component, poses Na0.5[Ni0.23Fe0.13Mn0.63]O2 among the best promising materials for the next generation of sodium ion batteries

Hot-pressed, Dry, Nanocomposite, PEO-based Electrolyte Membranes. Ionic Conductivity Characterization and Battery Tests

http://www.electrochem.org/dl/ma/203/pdfs/0098.pd

Leveraging valuable synergies by combining alloying and conversion for lithium-ion anodes

The essential need for new lithium-ion battery materials providing higher energy and power densities has triggered an exceptional increase in scientific and industrial research efforts in recent years. Regarding the anode side, the two major research directions to achieve improved energy densities have, so far, focused on materials which can host lithium either by alloying or by a conversion mechanism. Very recently, however, a new class of potential next generation anodes is gaining continuously increasing attention: conversion/alloying materials. Herein, we provide for the first time a comprehensive review on this new materials\u27 class. Initially, we discuss the two possible approaches to realize a combined conversion and alloying mechanism in a single compound, starting either from pure conversion or pure alloying materials. Based on this overview we subsequently highlight the fundamental insights and their potential advantages, which shall provide scientists with some general considerations and principles for the development of new, further enhanced conversion/alloying materials

A lithium-ion battery based on a graphene nanoflakes ink anode and a lithium iron phosphate cathode

Li-ion rechargeable batteries have enabled the wireless revolution transforming global communication. Future challenges, however, demands distributed energy supply at a level that is not feasible with the current energy-storage technology. New materials, capable of providing higher energy density are needed. Here we report a new class of lithium-ion batteries based on a graphene ink anode and a lithium iron phosphate cathode. By carefully balancing the cell composition and suppressing the initial irreversible capacity of the anode, we demonstrate an optimal battery performance in terms of specific capacity, i.e. 165 mAhg-1, estimated energy density of about 190 Whkg-1 and life, with a stable operation for over 80 charge-discharge cycles. We link these unique properties to the graphene nanoflake anode displaying crystalline order and high uptake of lithium at the edges, as well as to its structural and morphological optimization in relation to the overall battery composition. Our approach, compatible with any printing technologies, is cheap and scalable and opens up new opportunities for the development of high-capacity Li-ion batteries.Comment: 17 pages, 10 figure

Variation in Community Structure across Vertical Intertidal Stress Gradients: How Does It Compare with Horizontal Variation at Different Scales?

In rocky intertidal habitats, the pronounced increase in environmental stress from low to high elevations greatly affects community structure, that is, the combined measure of species identity and their relative abundance. Recent studies have shown that ecological variation also occurs along the coastline at a variety of spatial scales. Little is known, however, on how vertical variation compares with horizontal variation measured at increasing spatial scales (in terms of sampling interval). Because broad-scale processes can generate geographical patterns in community structure, we tested the hypothesis that vertical ecological variation is higher than fine-scale horizontal variation but lower than broad-scale horizontal variation. To test this prediction, we compared the variation in community structure across intertidal elevations on rocky shores of Helgoland Island with independent estimates of horizontal variation measured at the scale of patches (quadrats separated by 10s of cm), sites (quadrats separated by a few m), and shores (quadrats separated by 100s to 1000s of m). The multivariate analyses done on community structure supported our prediction. Specifically, vertical variation was significantly higher than patch- and site-scale horizontal variation but lower than shore-scale horizontal variation. Similar patterns were found for the variation in abundance of foundation taxa such as Fucus spp. and Mastocarpus stellatus, suggesting that the effects of these canopy-forming algae, known to function as ecosystem engineers, may explain part of the observed variability in community structure. Our findings suggest that broad-scale processes affecting species performance increase ecological variability relative to the pervasive fine-scale patchiness already described for marine coasts and the well known variation caused by vertical stress gradients. Our results also indicate that experimental research aiming to understand community structure on marine shores should benefit from applying a multi-scale approach

Diversity of Meiofauna from the 9°50′N East Pacific Rise across a Gradient of Hydrothermal Fluid Emissions

Background: We studied the meiofauna community at deep-sea hydrothermal vents along a gradient of vent fluid emissions in the axial summit trought (AST) of the East Pacific Rise 9 degrees 50'N region. The gradient ranged from extreme high temperatures, high sulfide concentrations, and low pH at sulfide chimneys to ambient deep-sea water conditions on bare basalt. We explore meiofauna diversity and abundance, and discuss its possible underlying ecological and evolutionary processes. Methodology/Principal Findings: After sampling in five physico-chemically different habitats, the meiofauna was sorted, counted and classified. Abundances were low at all sites. A total of 52 species were identified at vent habitats. The vent community was dominated by hard substrate generalists that also lived on bare basalt at ambient deep-sea temperature in the axial summit trough (AST generalists). Some vent species were restricted to a specific vent habitat (vent specialists), but others occurred over a wide range of physico-chemical conditions (vent generalists). Additionally, 35 species were only found on cold bare basalt (basalt specialists). At vent sites, species richness and diversity clearly increased with decreasing influence of vent fluid emissions from extreme flow sulfide chimney (no fauna), high flow pompei worm (S: 4-7, H-loge': 0.11-0.45), vigorous flow tubeworm (S: 8-23; H-loge': 0.44-2.00) to low flow mussel habitats (S: 28-31; H-loge': 2.34-2.60). Conclusions/Significance: Our data suggest that with increasing temperature and toxic hydrogen sulfide concentrations and increasing amplitude of variation of these factors, fewer species are able to cope with these extreme conditions. This results in less diverse communities in more extreme habitats. The finding of many species being present at sites with and without vent fluid emissions points to a non endemic deep-sea hydrothermal vent meiofaunal community. This is in contrast to a mostly endemic macrofauna but similar to what is known for meiofauna from shallow-water vents