The lithium-ion battery is the power source for most modern electric vehicles. Each battery is made up of many smaller units, called cells. The electrical current reaches these cells via conductive surfaces, including aluminum and copper. There is a positive electrode, the cathode, and a negative electrode, the anode. The battery is filled with a transport medium, the electrolyte, so the lithium ions carrying the battery’s charge can flow freely from one electrode to the other. This electrolyte solution needs to be extremely pure in order to ensure efficient charging and discharging.
Virtually every lithium ion cell produced today uses ethylene carbonate (EC), and most battery scientists believe it is essential. Petibon et al. (2016) tested electrolyte systems other than this within Li-Ion battery cells. Surprisingly, totally removing all ethylene carbonate from typical organic carbonate-based electrolytes and adding small amounts of electrolyte additives creates cells that are better than those containing ethylene carbonate. Petibon et al. (2016) used different surface coatings, electrolyte additives, and new solvent systems, and the impact was substantial. Continue reading →
In 1800, Italian physicist Alessandro Volta published results of an experiment he named the Voltaic pile. This stack of zinc and copper is now known as the first electrical battery. Since then, batteries have become increasingly smaller, more powerful, and more efficient. In 1991, the lithium-ion battery was introduced, having the highest energy density and slowest loss of charge in the rechargeable battery market. Today, energy storage and usage rely more heavily on natural energy harvested from their environment. These systems, including solar power, wind energy, or salinity gradients, are becoming more popular due to their renewable nature. However, the power that is generated from using these natural sources fluctuates randomly with time. In the case of solar cells, power attained in one unit could range from 1 μW to 100 mW, a scale 100,000 times different. Hence, charging and discharging these systems are much more variable than in conventional systems.
Bhat et a.l (2017) attempt to fundamentally change the way harvested energy is stored and used in batteries with different efficiencies. Whenever naturally harvested power is lower than the power required for system operation, a system cannot run from that source alone. First, energy must be stored in a battery, then simultaneously drawn from the battery and the natural source, enabling the system to run from the combined power. Continue reading →