Energy Density of a Typical 12-Volt Lithium Battery

Lithium batteries have rocked traditional power options with their superior capabilities and long lifespan. Their high energy density and fast charging capability make them a perfect choice for emergency power backups, remote alarm or surveillance systems, and lightweight marine power systems. They also have a vast range of other applications, particularly in the realm of automation and robotics. Their ability to retain charge over extended periods of time makes them ideal for powering drones, electric sprayers, or RC vehicles.

There are several types of lithium-ion batteries, each with a unique internal chemistry that gives rise to its energy densities. Most share a basic design of an aluminium backing on the cathode, carbon or graphite anode, and a separator that sits between these elements. Manufacturers experiment with the materials used on the cathode & anode, and with the composition of the electrolyte (lithium salt in an organic solvent). These changes are what differentiate a battery’s performance from one to the next.

A typical 12 volt lithium battery has an average energy density of 200-300 Wh/kg. Of this, 4 kg is in the cell with 2 kg in the anode, 1 kg in the current collectors and 0.6 kg in the separators. The balance is in the cell enclosure and the other lithium ions are distributed around the system with the aid of the electrolyte.

What is the Energy Density of a Typical 12-Volt Lithium Battery?

The biggest improvement potential is in the anode, which currently accounts for 80% of the total battery volume. Today’s graphite anodes intercalate a single lithium ion for every 6 graphite atoms, yielding a theoretical capacity of 372 mAh/g. Various alternative anode materials have been proposed, but they tend to require higher voltages, which reduces energy density.

There’s an equally large improvement opportunity in the cathode. Today’s Li-ion batteries use a mixture of nickel, manganese, cobalt, and lithium. While each material has its own advantages, they all have drawbacks, including high manufacturing costs and poor cycling performance at elevated temperatures. A battery with a single-metal cathode could achieve up to 40 MJ/kg, but this would increase the cost and complexity significantly.

Other opportunities exist in the anode, current collectors, and the separators. All of these components can be improved by switching to less costly materials and through technological advances, which can lower their sensitivity to high operating voltages.

There’s a lot of work to be done on improving the overall battery design. A more efficient, low-cost cathode material is one key piece of this puzzle. It’s also possible to reduce the size of the battery, which will have a major impact on its energy density. A battery with a smaller footprint would be lighter, cheaper, and more environmentally friendly. And, a smaller battery would enable greater application of advanced Li-ion technologies such as asymmetrical cell architectures or polymer electrolytes. The latter will allow for ultra-thin, flat cells that can fit into many more types of devices. This will be a huge benefit to the portable electronics industry as it drives adoption of these battery-powered devices into the workplace, home, and car.