The specific energy of commercial lithium ion batteries has increased substantially, while the price of both cells and batteries have diminished since their introduction in 1991(Figure 1). The results of these improvements have led to wide acceptance of the batteries in a number of applications. In particular, hybrid, plug-in hybrid and pure electric vehicles have been widely developed with lithium ion batteries. In addition, lithium ion batteries in other vehicle types from scooters to bicycles to motorcycles as well as trucks and buses have also been developed and are becoming popular. Lithium ion cells are frequently used in drones or unmanned aerial systems (UAS). High to medium power applications such as power tools and mechanical devices such as mobile robots have also been strongly marketed. Energy storage devices related to electric grid applications are also on a strong growth trajectory.

The design and material changes which have enabled these advances will be discussed and the prospects for further growth in energy and power will be considered. Also, the need for higher charge rates and possible methods of improvement in charge rate will be considered in the search for improved charge times for vehicles and other higher power applications.

Figure 1 Development of lithium batteries during the period of 1970–2015, showing the cost (blue, left axis) and gravimetric energy density (from G. Crabtree, E. Kocs and L. Trahey, MRS Bulletin 40, 1067, 2015)