Basic Research Needs for Electrical Energy Storage: Report of the ...

nanostructured, high-surface-area electrode scaffolds that host the fluid electrolyte and
provide current collection while also providing dispersed catalysts to promote redox
reactions at the electrode. For example, sodium batteries may deserve renewed attention,
particularly if suitable room-temperature molten salts can be identified, whereas a reversible
Li/Li2O2 (Li-air) system 9,10 with an ultraporous catalyzed nanoarchitecture for the air cathode
offers promise for significantly increasing the energy density of state-of-the-art batteries.
Currently, no batteries can meet the criteria that are required for tomorrow’s energy storage
needs (see Factual Document, Appendix A). While battery technologies have been optimized
to some extent, they have remained essentially the same for many decades. For example, the
laminated cell design used commercially today is strikingly similar to the original design of
Volta, now more than 200 years old. Changes have been evolutionary to meet changing
performance criteria, but radical, revolutionary approaches that consider the entire system are
required to provide batteries that meet these criteria. Fundamental research is needed to
identify broad areas in materials and chemical sciences where advances can have dramatic
societal impact.
Research Directions
New materials and chemistries are required for the radical improvements in energy and
power densities of chemical energy storage systems for transportation and electrical grid
applications. Basic research efforts will require interdisciplinary teams of materials and
chemical scientists to elucidate the fundamental processes that occur in chemical energy
storage systems, including (1) understanding the basis for the design and synthesis of new
anode and cathode materials and cell chemistries; (2) establishing the principles controlling
electrode surfaces and electrode-electrolyte interfaces; (3) characterizing physical, chemical,
and dynamic electrochemical properties; and (4) theoretical modeling of electrode structure
and design and electrochemical phenomena. Specific aspects that should be included in new
research are discussed in the following sections.
Tailored nanostructured electrode materials. Stable, high-potential materials (>4 V) may
be achieved through tailored introduction of anions, structural modifications, and
defects/disorder. These nanostructured materials could be designed to create stable
multifunctional surface layers to access and increase capacity and power and maintain
electronic conductivity at all times during electrochemical cycling. For example, porous
nanostructured materials could be embedded with catalysts to increase capacity and reaction
rates with gaseous electrodes. Multifunctional materials can be envisioned for use in
electrodes that will optimize the ionic transport, electronic conductivity, and stability of the
operating voltage of the cells. For example, battery electrodes are commonly made of
composites containing carbon to interconnect the active electrode particles electronically
with one another and with the current collector; Teflon, to bind the mass together; and pores
filled with electrolyte to provide a large-area electrode-electrolyte interface. Novel
electrochemically active, electronically conductive polymers are candidates for replacing
these components with tailored architectures that integrate the components, increasing the
charge storage capacity per electrode mass.
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