According to reports, California-based Amprius has produced the first lithium batteries that claim to be the most energy-dense of the batteries currently available. By weight, these batteries have 73 percent more energy than Tesla Model 3 batteries, while reducing volume by 37 percent.
According to Enpower, Tesla's current Model 3 battery is state-of-the-art, with an energy density of about 260 Wh/kg (730 Wh/l). The latest Amprius batteries are a major improvement in both specific energy (energy emitted per unit electrode) and energy density, with a battery capacity of 450Wh/kg (1150 Wh/l).
Amprius says the battery's impressive performance is attributed to its silicon nanowire anode technology. Currently when you charge a lithium-ion battery, you can efficiently pull an electron out of the cathode of each lithium atom and move them to the anode via an external wiring, because the electrons cannot pass through the electrolyte or diaphragm between the anode and the cathode. Their negative charge pulls the positively charged lithium ions through the electrolyte and diaphragm, where they each find an electron and embed it into the typical graphite lattice of the anode.
Now, Amprius has replaced the graphite lattice with silicon nanowires. Silicon can store 10 times more lithium than graphite, but it is prone to expansion and rupture, greatly reducing battery life. The company says that when you form silicon into porous nanowires, arranged into a "forest" of longer and shorter wires, silicon is able to resist expansion and cracking, extending the life of the battery and making the silicon anode a competitive technology.
The company says the silicon nanowires are rooted exactly in the substrate of the anode, so the conductivity (and power) is high. It said the battery's cycle life was "excellent" and "constantly improving," though it didn't give any numbers, and it also said that the anode was the only part of the battery that was different from other existing batteries, and the rest could be produced using existing manufacturing methods and components.
Clearly, the world is ready to embrace the next generation of batteries, hoping that the new generation of batteries can store more energy in smaller sizes and weights – everything from smartphones to electric cars will benefit from a reduction in weight or space, and emerging technologies such as electric VTOL aircraft desperately need batteries to improve flight distance and flight capabilities.
Of course, energy density and specific energy are just two indicators that batteries need to compete with. Thermal performance, safety, charge-discharge rate and cycle life will all play an important role, and price will also play an important role. In fact, Amprius' first customers were in the advanced aerospace and satellite manufacturing sectors, which means the battery is still not competitive in terms of price.