reverse engineering How we made the Li-ion rechargeable battery Progress in portable and ubiquitous electronics would not be possible without rechargeable batteries. John B. Goodenough recounts the history of the lithium-ion rechargeable battery. John B. Goodenough

battery contains one or many – – electrolyte. As a result, the program was identical cells. Each cell stores electric e e abandoned a few years later. Apower as chemical energy in two _ + Around this time, my group at the electrodes, the anode and the cathode, University of Oxford was investigating which are separated by an electrolyte. how much lithium can be extracted from

The chemical reaction between the a layered lithium cobalt oxide (LiCoO2) or Li+ electrodes has an ionic and an electronic lithium nickel oxide (LiNiO2) before the component. The electrolyte transports the structure changed. I had reasoned that a ionic component inside a cell and forces rechargeable battery could be fabricated the electronic component to traverse an in a discharged, as well as a charged, state. external circuit. In a rechargeable battery, We were able to demonstrate that over half the chemical reaction is reversible. Li+ of the lithium could be extracted reversibly In the 1960s, chemists in Europe with these cathode materials. This led + were exploring the chemistry of reversible Li Akira Yoshino, then at the Asahi Kasei insertion of lithium into layered Corporation, to make the first lithium-ion transition-metal sulfides. At that time, rechargeable battery by combining the rechargeable batteries used strongly LiCoO2 cathode with a graphitic-carbon Anode Electrolyte Cathode acidic (H2SO4) or alkaline (KOH) aqueous anode (Fig. 1). This battery was used electrolytes that offered fast hydrogen-ion Fig. 1 | Components of a rechargeable Li-ion battery. by the Sony Corporation to power the (H+) diffusion. The most stable cells used very first portable phone. an alkaline electrolyte and a layered nickel To lower the cost and increase safety, an oxyhydroxide (NiOOH) as the cathode into all-solid-state rechargeable battery — where which H+ is inserted reversibly to form the The oil crisis of the early 1970s exposed the liquid electrolyte is replaced with a solid hydroxide Ni(OH)2. However, an aqueous the vulnerability of US society, among electrolyte — is an active future direction electrolyte limits the voltage of the cell and, others, to its dependence on imported oil for battery research. Indeed, rechargeable therefore, the density of electric power a and subsequently prompted investigations batteries with solid electrolytes are now battery can deliver. into solar and wind energy as potential being developed, including sodium In 1967, Joseph Kummer and Neill Weber sources for electric power. However, the batteries with a NASICON electrolyte. of the Ford Motor Company discovered intermittency of solar and wind meant that In 2015, a remarkable dielectric amorphous- fast sodium-ion diffusion above 300 °C storage of this power would be required oxide solid electrolyte was brought to me in a ceramic electrolyte and invented a for these renewable sources to be useful. by Maria Helena Braga of the University sodium–sulfur rechargeable battery that Hence, there was a desire for better of Porto. It has lithium and sodium ion used the solid ceramic as the electrolyte, rechargeable batteries. conductivities comparable to those of the molten sodium as the anode and molten Non-rechargeable batteries using a organic-liquid electrolytes used in today’s sulfur containing carbon felt as the cathode. lithium anode and an organic-liquid lithium-ion batteries. At the University of The high operating temperature of above electrolyte were known at the time, so Texas at Austin, where I moved to in 1986, 300 °C made their battery commercially the next step was to use the chemistry we have used this unique solid to develop impractical, but it stimulated research into demonstrated in Europe of reversible all-solid-state rechargeable batteries that solid electrolytes and alternative battery lithium-ion insertion into transition-metal are able to plate dendrite-free alkali-metal strategies. At the time, I was working on layered sulfide cathodes in order to create a anodes with good contact over a long cycle transition-metal oxides at the MIT Lincoln rechargeable battery. Stanley Whittingham life at acceptable charge and discharge rates. Laboratory, and I was asked to monitor the was hired by the Exxon Mobil Corporation These developments suggest that all-solid- development of this battery. The assignment to create such a rechargeable battery with state batteries may soon be used to power introduced me to electrochemistry and a layered titanium disulfide (TiS2) cathode all-electric road vehicles that are competitive to the challenge of developing a better that discharged to LiTiS2 through reversible with vehicles powered by fossil fuel in an oxide-based sodium-ion conductor. lithium insertion. In 1976, Whittingham internal combustion engine. ❐ In response, I developed, together with reported good initial performance for

Henry Hong, a Na1+xZr2SixP3−xO12 electrolyte the cell. However, on repeated charging, John B. Goodenough that had a framework structure and plating of the lithium anode resulted in University of Texas at Austin, Austin, TX, USA. supported fast sodium ion conductivity; the formation of anode dendrites (lithium e-mail: [email protected] it was dubbed NASICON (NA SuperIonic whiskers) that grew across the electrolyte CONductor) by colleagues after I left for to the cathode to create an internal short Published online: 9 March 2018 the University of Oxford in 1976. circuit, which would ignite the flammable https://doi.org/10.1038/s41928-018-0048-6

204 Nature Electronics | VOL 1 | MARCH 2018 | 204 | www.nature.com/natureelectronics © 2018 Macmillan Publishers Limited, part of Springer Nature. All rights reserved. © 2018 Macmillan Publishers Limited, part of Springer Nature. All rights reserved.