Battery Technology Advances Explained

Batteries are the unsung heroes of the modern world. They power our smartphones, laptops, and electric vehicles, and they are increasingly crucial for storing renewable energy to create a stable power grid. For the past few decades, the lithium-ion battery has been the reigning champion, driving the portable electronics revolution and making electric cars practical. But as the demand for more powerful, longer-lasting, and safer batteries grows, a new generation of battery technology is on the horizon.

The research and development in battery technology is focused on a few key areas: increasing energy density, improving safety, extending lifespan, and reducing cost by using more abundant materials.

The Next Step: Solid-State Batteries

One of the most anticipated advances in battery technology is the solid-state battery. A conventional lithium-ion battery has three main components: a positive electrode (cathode), a negative electrode (anode), and a liquid electrolyte that allows lithium ions to flow between them. This liquid electrolyte is typically flammable, which can pose a safety risk.

A solid-state battery, as the name suggests, replaces this liquid electrolyte with a solid one. This solid material can be a ceramic, a polymer, or a glass. This seemingly simple change has several profound benefits.

• Safety. By removing the flammable liquid, solid-state batteries are much safer and less prone to catching fire if they are damaged or overheat.
• Energy Density. The solid electrolyte allows for the use of more advanced anode materials, most notably pure lithium metal. A lithium-metal anode can store much more energy than the graphite anodes used in today's lithium-ion batteries. This could lead to electric vehicles with a much longer range or smartphones that last for days on a single charge.
• Faster Charging. Solid-state batteries have the potential to charge much faster than their liquid-based counterparts.

The challenge with solid-state batteries is manufacturing them at scale. It's difficult to maintain perfect contact between the solid electrodes and the solid electrolyte, and the materials can be brittle. Many companies, from major automakers to startups, are racing to solve these engineering challenges, and the first solid-state batteries are expected to appear in high-end electric vehicles in the coming years.

Beyond Lithium-Ion: New Chemistries

While solid-state batteries improve on the lithium-ion design, other researchers are exploring entirely new battery chemistries that don't rely on cobalt and nickel, which are expensive and have supply chain concerns.

• Lithium-Sulfur Batteries. Sulfur is abundant and cheap, and lithium-sulfur batteries have a theoretical energy density that is much higher than lithium-ion. The main challenge is that they have a short lifespan; they can't be charged and discharged many times. Researchers are working on new electrode and electrolyte designs to improve their durability.

• Sodium-ion Batteries. Sodium is in the same group as lithium on the periodic table and has similar chemical properties. More importantly, it is thousands of times more abundant than lithium and much cheaper. Sodium-ion batteries have a lower energy density than lithium-ion, so they might not be suitable for high-performance electric cars, but they are a very promising candidate for stationary grid storage, where cost is more important than weight.

Grid-Scale Storage Solutions

For storing massive amounts of energy on the power grid, the requirements are different than for a car or a phone. Cost and lifespan are far more important than size and weight. This has led to the development of specialized grid-scale storage technologies.

Iron-air batteries are an emerging technology for long-duration storage. They work by a process of "rusting" and "un-rusting." To charge, the battery uses electricity to turn iron oxide (rust) into metallic iron. To discharge, it exposes the iron to air, and the iron "rusts" again, releasing energy. These batteries use abundant and cheap materials (iron, water, and air) and could be a very low-cost solution for storing energy for days at a time.

Flow batteries, which store energy in large tanks of liquid electrolyte, are another solution for long-duration storage. The ability to scale their capacity simply by using bigger tanks makes them a flexible and cost-effective option for grid applications.

The pace of innovation in battery technology is faster than ever before. From solid-state batteries that will power the next generation of electric vehicles to low-cost iron-air batteries that will help us build a 100% renewable grid, these advances are critical for creating a more sustainable and electrified future. The quiet revolution happening inside these small devices will have a loud impact on our world.

Frequently Asked Questions (FAQs)

1. When will solid-state batteries be available in consumer products? Several car manufacturers have announced plans to introduce vehicles with solid-state batteries in the latter half of the 2020s. They will likely appear in high-end luxury models first, and then become more mainstream as manufacturing costs come down.

2. Are we going to run out of lithium? While lithium is a finite resource, current global reserves are sufficient to meet the projected demand for electric vehicles and energy storage for the foreseeable future. More importantly, the battery industry is investing heavily in recycling, which will create a circular economy where the lithium from old batteries can be used to make new ones. New battery chemistries that use more abundant materials like sodium will also help to reduce the demand for lithium.

3. What is the difference between energy density and power density? Energy density refers to how much energy a battery can store for a given size or weight. A battery with high energy density can power a car for a long range. Power density refers to how quickly a battery can deliver that energy. A battery with high power density can provide rapid acceleration. These two properties are often in a trade-off with each other.