Editorial pubs.acs.org/CR
Introduction: Batteries which resides the electrolyte. To ensure that the anode and cathode do not contact each other and short out the cell, a separator is placed between the two electrodes. Most of these critical components are discussed in this special issue. The first three papers relate to Li-ion batteries. Whittingham discusses the present status of intercalation cathodes with an emphasis on understanding the reaction mechanism using two model compounds, LiFePO4 and VOPO4, and gives an indication of the ultimate limits of batteries based on intercalation, that is where lithium is held in a host material. The second paper, by Obrovac, describes the next generation anodes for lithium batteries. The third, by Xu, gives an in-depth review of the third critical area, electrolytes and interphases. The next paper, by Aravindan, is also concerned with Li-ion systems but with the emphasis on capacitors. The next group of papers describe next generation systems, that are under intense study, the first two of which still use intercalation chemistry but with either sodium or magnesium as the anode. Komaba describes the potentially lower cost sodium systems, and Muldoon describes magnesium systems which offer the opportunity for 2 electrons per redox center, but with many challenges. Then two even more challenging systems based on conversion reactions of lithium with oxygen and sulfur are described by Luntz and Manthiram, respectively. Essentially all the above papers use nonaqueous electrolytes. Kang describes some possible water based batteries for both intercalation and conversion chemistries. The final paper, by Mai, looks at the role that nanowires can play again in both intercalation and conversion reaction-based batteries.
This thematic issue follows a similar issue on batteries and fuel cells 10 years ago, and it builds on that issue.1 Thus, the reader is referred to the articles there for a historical perspective. The reader is also referred to the article by Winter and Brodd2 in that issue for a general introduction to batteries and the associated electrochemistry. The articles here cover the electrochemical storage of energy in batteries, an area gaining tremendous importance for powering high technology devices, for enabling a greener and less energy intensive transportation industry, as well as for enabling renewable energy such as solar and wind. There is also an increasing desire for a Smart Grid that among other attibutes can protect the infrastucture, in the event of future natural disasters such as hurricane Sandy. Although there are lower cost methods of storing electrical energy, such as pumped hydro, there are few sites where future systems can be built, so the emphasis is firmly focused on batteries, both for portable and stationary apllications.3 Whether the demand is for a microbattery for a smart card or a 32 MWh wind grid facility, the consumer is demanding a longer life in a smaller package and at a lower cost. In the area of greener transportation, there has been a surge of interest in electric vehicles, either totally electrically powered, such as the Tesla or Nissan Leaf, or partially electrically powered, as in hybrid electric vehicles, pioneered by the Toyota Prius. As several countries begin to generate more than 10% of their electricity from solar or wind, there becomes a critical need for storage; batteries and/or supercapacitors are also needed to smooth the output from such facilities. To address these challenges, major research consortia have been formed around the globe. Japan, the European Community, Germany, and France all have large multi-institutional groups addressing the fundamentals of battery chemistry. Britian is now also mounting an effort. In the United States, the Department of Energy in 2009 began funding 46 Energy Frontier Research Centers, several of which focused on energy storage.4 Now in the second round of funding, five Centers will continue building an understanding of the fundamentals of electrochemical energy storage; some of these now have international partners. In 2012 an even larger “JCESR Hub” effort was initiated at Argonne National Laboratory, which covers all aspects from fundamental understanding to prototype modeling and evaluation.5 At the same time, consortia of manufacturers, investors, governments entities, and users are being assembled to assist in the deployment of energy storage.6 Batteries utilize controlled chemical reactions, in which the desired chemical reaction occurs electrochemically, and all other reactions, including corrosion ones, are hopefully absent or severely kinetically controlled. This desired selectivity demands careful selection of the chemical components, including their morphology and structure; nanosize is not necessarily good, and in present commercial lithium batteries the particle sizes are often intentionally large. All batteries contain an electropositive electrode (the anode) and an electronegative electrode (the cathode or oxidant) between © 2014 American Chemical Society
M. Stanley Whittingham*
Chemistry and Materials, State University of New York at Binghamton
AUTHOR INFORMATION Corresponding Author
*E-mail:
[email protected]. Notes
Views expressed in this editorial are those of the author and not necessarily the views of the ACS.
REFERENCES (1) Batteries and Fuel Cells Thematic Issue. Chem. Rev. 2004, 104 (10), 4243−4886. (2) Winter, M.; Brodd, R. J. Chem. Rev. 2004, 104, 4245. (3) Whittingham, M. S. Proc. IEEE 2012, 100, 1518. (4) NorthEast Center for Chemical Energy Storage, http://necces. binghamton.edu (accessed November 7, 2014). (5) Joint Center for Energy Storage Research, http://www.jcesr.org (accessed November 7, 2014). (6) New York Battery and Energy Storage Technology consortium, http://www.ny-best.org (accessed November 7, 2014).
Special Issue: 2014 Batteries Published: December 10, 2014 11413
dx.doi.org/10.1021/cr500639y | Chem. Rev. 2014, 114, 11413−11413
