60
more commonly as the ZEBRA battery (Zeolite Battery Research Africa Project or
more recently, Zero-Emission Battery Research Activities), was originally patented
in 1975 and was pursued as an alternative to the NaS battery [2]. Until recently,
however, these technologies have found relatively little utility, despite tremendous
potential technical value. Historical problems with battery cost, safety, operational
temperature, and long-term performance have resulted in relatively limited demand
for these kinds of batteries. Over the past 10–20 years, however, the explosive
increase in demand for the storage and distribution of electrical energy has motivated a renewed interest in a variety of battery technologies. There is clear opportunity for sodium-based batteries to fill critical gaps in the current electrical energy
storage technology portfolio. Generally speaking, there are many different sodiumbased battery technologies emerging to meet the varied global demand for batteries,
ranging from sodium-ion and flow batteries to solid-state systems. This chapter,
however, will specifically focus on molten sodium batteries with an emphasis on the
materials science of these promising battery systems. It will introduce existing battery chemistries, highlight some of the challenges with the current state of the art,
and discuss opportunities to advance these batteries in the coming years.
1.2 Battery Development Considerations
Despite the focus of this chapter on molten sodium batteries, it is important to note
that the integration of batteries into the emerging global energy storage future will
almost certainly include a multitude of chemistries and technologies as no single
battery technology is “right” for every application. Batteries are essentially electrochemical reactors, and both the advantages and limitations of each chemically distinct reactor should be considered when selecting a battery system for a particular
application. Requirements related to how much energy a battery can store and how
quickly, or slowly, the system can be charged and discharged matter a great deal.
The functional lifetime of the battery, particularly for secondary (rechargeable) batteries, is also important, affecting not only performance, but also the effective cost
of a system. Factors such as a battery’s size or weight, if it will be stationary or
mobile, and the climate where the battery will be used should also be taken into
consideration. The safety of the battery is an important factor as well and has drawn
substantial interest recently. It is important to ask if there are any hazardous side
reactions to be aware of, either during normal operations or in the event of an unexpected assault on or failure within the battery. Widely publicized fires from failing
lithium-ion batteries, for example, highlight the importance of this issue, both for
applications in ubiquitous personal electronics and for very large grid-scale systems
with much higher consequences of failure. It should be noted that although molten
sodium batteries were originally conceived and developed for transportation applications, current battery development of these technologies is focused largely on
grid-scale energy storage. Current research has an eye on all of these factors, with
different chemistries providing or emphasizing different solutions based on
application- dependent requirements.
E. D. Spoerke et al.
more commonly as the ZEBRA battery (Zeolite Battery Research Africa Project or
more recently, Zero-Emission Battery Research Activities), was originally patented
in 1975 and was pursued as an alternative to the NaS battery [2]. Until recently,
however, these technologies have found relatively little utility, despite tremendous
potential technical value. Historical problems with battery cost, safety, operational
temperature, and long-term performance have resulted in relatively limited demand
for these kinds of batteries. Over the past 10–20 years, however, the explosive
increase in demand for the storage and distribution of electrical energy has motivated a renewed interest in a variety of battery technologies. There is clear opportunity for sodium-based batteries to fill critical gaps in the current electrical energy
storage technology portfolio. Generally speaking, there are many different sodiumbased battery technologies emerging to meet the varied global demand for batteries,
ranging from sodium-ion and flow batteries to solid-state systems. This chapter,
however, will specifically focus on molten sodium batteries with an emphasis on the
materials science of these promising battery systems. It will introduce existing battery chemistries, highlight some of the challenges with the current state of the art,
and discuss opportunities to advance these batteries in the coming years.
1.2 Battery Development Considerations
Despite the focus of this chapter on molten sodium batteries, it is important to note
that the integration of batteries into the emerging global energy storage future will
almost certainly include a multitude of chemistries and technologies as no single
battery technology is “right” for every application. Batteries are essentially electrochemical reactors, and both the advantages and limitations of each chemically distinct reactor should be considered when selecting a battery system for a particular
application. Requirements related to how much energy a battery can store and how
quickly, or slowly, the system can be charged and discharged matter a great deal.
The functional lifetime of the battery, particularly for secondary (rechargeable) batteries, is also important, affecting not only performance, but also the effective cost
of a system. Factors such as a battery’s size or weight, if it will be stationary or
mobile, and the climate where the battery will be used should also be taken into
consideration. The safety of the battery is an important factor as well and has drawn
substantial interest recently. It is important to ask if there are any hazardous side
reactions to be aware of, either during normal operations or in the event of an unexpected assault on or failure within the battery. Widely publicized fires from failing
lithium-ion batteries, for example, highlight the importance of this issue, both for
applications in ubiquitous personal electronics and for very large grid-scale systems
with much higher consequences of failure. It should be noted that although molten
sodium batteries were originally conceived and developed for transportation applications, current battery development of these technologies is focused largely on
grid-scale energy storage. Current research has an eye on all of these factors, with
different chemistries providing or emphasizing different solutions based on
application- dependent requirements.
E. D. Spoerke et al.