Manipulation of matter at the nanoscale is a way forward to move beyond our current choices in electrochemical energy storage and conversion technologies with promise of higher efficiency, environmental benignity, and cost-effectiveness. Electrochemical processes being basically surface phenomena, tailored multifunctional nanoarchitecturing can lead to improvements in terms of electronic and ionic conductivities, diffusion and mass transport, and electron transfer and electrocatalysis. The nanoscale is also a domain in which queer properties surface: those associated with conversion electrodes, ceramic particles enhancing the conductivity of polymer electrolytes, and transition metal oxide powders catalyzing fuel cell reactions, to cite a few. Although this review attempts to present a bird's eye view of the vast literature that has accumulated in this rather infant field, it also lists a few representative studies that establish the beneficial effects of going `nano'. Investigations on nanostructuring and use of nanoparticles and nanoarchitectures related to lithium-ion batteries (active materials and electrolytes), supercapacitors (electrical double-layer capacitors, supercapacitors based on pseudo-capacitance, and hybrid supercapacitors), and fuel cells (electrocatalysts, membranes and hydrogen storage materials) are highlighted. (C) 2012 John Wiley & Sons, Ltd.

Nanostructured electrode materials for electrochemical energy storage and conversion

All carbon based high energy lithium-ion capacitors from biomass: The role of crystallinity

The present invention provides a dispersible and electrically conductive nano graphene platelet (NGP) material comprising at least a single-layer or multiple-layer graphene sheet, wherein the NGP material has an oxygen content no greater than 25% by weight and no less than 5% by weight. This NGP material can be produced by: (a) preparing a pristine NGP material from a graphitic material; and (b) subjecting the pristine NGP material to an oxidation treatment. Alternatively, the production process may comprise: (A) preparing a graphite oxide (GO) from a laminar graphite material; (b) exposing the GO to a first temperature for a first period of time to obtain exfoliated graphite; and (c) exposing the exfoliated graphite to a second temperature in a protective atmosphere for a second period of time. Conductive NGPs can find applications in transparent electrodes for solar cells or flat panel displays, additives for battery and supercapacitor electrodes, conductive nanocomposite for electromagnetic wave interference (EMI) shielding and static charge dissipation, etc.

Dispersible and conductive nano graphene platelets

A battery includes an anode, a cathode, and an electrolyte disposed between the anode and the cathode. The cathode includes a hollow structure defining an internal volume and a sulfur-based material disposed within the internal volume. A characteristic dimension of the internal volume is at least 20 nm, and the sulfur-based material occupies less than 100% of the internal volume to define a void.

Encapsulated sulfur cathodes for rechargeable lithium batteries

This chapter discusses lithium-ion battery chemistries, designs, and trends for hybrid electric vehicles (HEVs) and battery electric vehicles (EVs). The main development focus of HEV and EV batteries is on higher energy densities, safety, lifetime, and costs. On the cell level, different cell formats and cell chemistries are discussed and the general battery pack design is ­highlighted. Expected future trends and developments for cathode chemistry 5 V materials and for silicon alloy anodes are discussed. For battery packs, the major focus is on lightweight construction and cost-efficient electric and electronic architectures.

Lithium-ion batteries for hybrid electric vehicles and battery electric vehicles

Graphites and hard carbons are the mainstay of anode materials in practical lithium-ion batteries. With their dominance beginning to be threatened by other alternative anode materials such as silicon and intermetallics, continual research is directed at exploring known carbonaceous materials as well as at synthesizing new carbon-based anodes. After a review of lithium storage mechanisms in various carbon forms, this article explores avenues for crossovers between chemistry and materials science for tailoring carbonaceous materials that can cater to increasing power demands of emerging technologies. In particular, this review suggests opportunities and problem areas in anodes based on carbon composites as well as novel carbonaceous materials such as kish graphites, carbon nanotubes, nanofibers, curved carbon lattices and graphenes that are expected to prolong the legacy of carbon in lithium-ion batteries.

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Manuel A Stephan

Papers

Carbonaceous anode materials for lithium-ion batteries - the road ahead