From Volta to Li-ion Batteries

In the long history of the development of electrochemical energy storage systems (batteries, accumulators), the advent of lithium metal, then lithium-ion (Li-ion) accumulators represents a major turning point. This technology combines a positive electrode with high oxidizing power with a negative electrode with high reducing power, both impregnated with a non-aqueous electrolyte and physically separated from each other by an ion-conducting and electronically insulating separator. Each cell generates a terminal voltage (electromotive force, or e.m.f.) of around 4 volts. This high voltage is a major advantage when it comes to storing large quantities of electrical energy in relation to the mass or volume of the battery (expressed in Wh · kg ^–1 or in Wh · L ^–1 ). Optimized choice of materials and advances in manufacturing processes since the first Li-ion batteries were marketed in 1991 (80 Wh · kg ^–1 and 200 Wh · L ^–1 ) have enabled us to achieve energy densities of around 250 Wh · kg ^–1 and 600 Wh · L ^–1 , as well as cycling lifetimes of the order of several thousand charge/discharge cycles. These performances are by far the highest obtained among rechargeable systems operating at ambient temperature.

The first Li-ion batteries, designed between 1985 and 1990 and marketed in the early 1990s by Japanese manufacturers Sony and Asahi Kasei, were intended to power camcorders. During an initial development phase that lasted some twenty years, significant improvements in performance and a steady fall in price enabled Li-ion batteries to meet the ever-increasing demands of the rapidly expanding consumer electronics market (laptops, cell phones, tablets, tools, household equipment, etc.). Several Asian manufacturers (Sanyo, Panasonic...) are following Sony's example, by integrating the manufacture of Li-ion batteries into their own factories. Li-ion batteries are an essential component of the final product they manufacture, since they largely determine its weight, size and cost. The nickel-cadmium (Ni-Cd) and then nickel-metal hydride (Ni-MH) aqueous electrolyte battery technologies initially used are rapidly giving way to Li-ion batteries in these markets. These strategic initiatives go a long way towards explaining the virtual monopoly that Japanese, Korean (LG, Samsung...) and, more recently, Chinese (BYD, CATL...) manufacturers have achieved in lithium battery production. Over the 2005-2015 period, the technological maturity achieved by these manufacturers in the sector is reflected not only in their mastery of large-scale manufacturing,...