For many years,nickel-cadmium had been the only suitable battery for portable equipment from wireless communications to mobile computing. Nickel-metal-hydride and lithium-ion emerged In the early 1990s,fighting nose-to-nose to gain customer’s acceptance.Today,lithium-ion is the fastest growing and most promising battery chemistry.Clean technologies increasingly depend on batteries,particularly lithium-ion battery.Everything from electric cars to renewable energy back-up storage,as well as almost all of our gadgets like smartphones and laptops use them.
In this new design,lithium ions flow from the cathode through the electrolyte,diffuse through the carbon shells,and enter the silicon-which can hold ten times as many lithium ions as carbon alone.”The coolest part of this new system is that the silicon nanoparticles swell when filled with the lithium ions,but don’t burst the carbon shell.The researchers say this new system is not only higher performing,but the manufacturing process to make these batteries is affordable,efficient and easily scaled up for higher production.
The energy density of lithium 18650 battery is typically twice that of the standard nickel-cadmium.There is potential for higher energy densities.The load characteristics are reasonably good and behave similarly to nickel-cadmium in terms of discharge.The high cell voltage of 3.6 volts allows battery pack designs with only one cell.Most of today’s mobile phones run on a single cell.A nickel-based pack would require three 1.2-volt cells connected in series.Lithium-ion is a low maintenance battery,an advantage that most other chemistries cannot claim.There is no memory and no scheduled cycling is required to prolong the battery’s life.In addition,the self-discharge is less than half compared to nickel-cadmium,making lithium-ion well suited for modern fuel gauge applications.
To really push these technologies forward,battery storage and performance has to increase without increasing in size.EMSL explains, “When in use,lithium ions flow from the cathode through an electrolyte into the anode,most commonly made of carbon.During recharging,the ions are pushed back to the cathode where they started.Researchers built upon current technology by making a new type of anode that consists of single silicon nanoparticles inside carbon shells,much like yolks inside eggs.
Researchers at the Environmental Molecular Sciences Laboratory (EMSL) think they’ve come up with a novel way to do just that by using silicon nanoparticles that swell to increase the amount of lithium ions that can be stored,resulting in lithium batteries system that can store seven times more energy and be discharged and recharged five times as many times as the current technology.This advance could lead to batteries that not only store much more energy,letting electronics run longer on a single charge,but batteries that have much longer lifetimes.
