The lithium-ion (Li-ion) battery is now the automotive industry’s workhorse in the production of electric vehicles (EVs). It was invented in the 1970s, when the 1973 oil crisis prompted Exxon to fund battery research that led to the development of this new technology by Stanley Whittingham (for which he was awarded the Nobel Prize in Chemistry in 2019, along with his colleagues John B. Goodenough and Akira Yoshino). It was commercialised by Sony in 1991 for use in electronic devices.
Battery operation
The Li-ion battery consists of a set of cells with two electrodes, separated by a liquid electrolyte, and which are the site of electrochemical reactions.1 The positive electrode (the cathode when the battery is charged) is made up of layers of lithium, cobalt (potentially replaced by nickel), and manganese oxides (in the case of the so-called NMC battery, which is the most widely used today), or lithium and iron phosphates, with lithium ions inserted (“intercalated”) in the anode in layers of graphite (in the case of the less expensive LFP battery, favoured by Tesla and Chinese manufacturers). The electrolyte is a liquid that separates the electrodes and allows the movement of electrical charges: this is a solution of lithium salts (phosphates, chlorides, and fluorides), either in ethylene or propylene carbonates, or in carboxylic esters. During discharge, the anode releases electrons into an external circuit, and positively charged lithium ions pass through the electrolyte and into the oxide layers of the cathode.
Source: Tarascon Jean-Marie, “What future for batteries?
1. Tarascon Jean-Marie, “What Future for Batteries?“, Pour la science, no. 522, April 2021, p. 44; and Tarascon Jean-Marie, “Material Science as a Cornerstone Driving Battery Research”, Nature Materials, vol. 21, September 2022, p. 979.
The electrical density of...
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