New Cathode Material Could Help Extend EV Battery Life for Years
November 25, 2011 2:51 PM
New cheap nanoparticle-based cathode for K+ batteries can survive 40,000 cycles with only modest degradation
The weakest point of the electric vehicle (EV) is arguably the very thing that powers it -- the battery. Tesla Motor Comp. (
its 245-mile (official range) Roadster
at 400 guaranteed charge cycles (a 98k mile life) similar to the General Motors Comp. (
40-mile (electric) range Chevy Volt
, which offers 2,500 charge cycles (a 100K mile all electric range) [
]. While 100,000 miles isn't the worst thing in the world, it also isn't great, considering the high up-front costs of EV ownership.
I. New Electrode is Survival Champion
Virtual all EVs and personal electronics rely on the same old lithium-ion batteries. But a new type of batteries – potassium-ion batteries -- intrigues with the potential for much greater durability.
has cooked up a cathode (high voltage electrode) for this type of battery capable of outlasting virtually any of its lithium ion peers. Created by graduate student Colin Wessells and his advisor, Yi Cui, an associate professor of materials science and engineering, the new material was able to deliver 80 percent or better charge delivery for 40,000 charges.
Better yet, the cathode material is inexpensive. Writes the researchers:
Here we show that crystalline nanoparticles of copper hexacyanoferrate, which has an ultra-low strain open framework structure, can be operated as a battery cathode in inexpensive aqueous electrolytes.
Mr. Wessells says the creation of the cathode compound is cheap and easy. He says he was able to create gram quantities, stating, "We put chemicals in a flask and you get this cathode material. You can do that on any scale. There are no technical challenges to producing this on a big-enough scale to actually build a real battery."
Stanford University has made a platinum free cathode using copper/Prussian Blue nanoparticles. The cathode is the perfect compliment to potassium ion electrolyte batteries.
[Image Source: Stanford University/Nature Communications]
II. From Paint Dye to Batteries
The chemical compound comprising the cathode -- Copper hexacyanoferrate (Cu
]) -- is also cheap from a chemical basis. It contains commonly occurring organic elements -- carbon and nitrogen (in the cyanide group) -- and metal elements -- copper and iron.
[abstract] has been done into make copper hexacyanoferrate nanoparticles efficiently. The hexacyanoferrate group is familiar to chemists and doctors as "Prussian Blue" -- a brilliant blue pigment used in paints and as a treatment to heavy metal poisoning.
Prussian Blue [Image Source: MadeInChina]
Ion batteries can go through heat-driven degradation in two primary ways. First, the electrolyte fluid can dry over time, losing moisture due to the heat they're exposed to during charging and use. Recent
[press release] from
Ohio State University
indicates that a second major issue is a fouling process involves ions damaging the cathode and becoming lodged inside it, creating compounded degradation.
The new material sounds particularly promising as a solution to the latter problem (the former problem can potentially be solved by some sort of chemical sensor and liquid reservoir).
Prussian Blue based potassium ion batteries have been dabbled with for over a decade.
erroneously indicate them to have been "invented" in 2004. In reality, while
[full text; PDF] on one design was published that year, another work using a Prussian Blue cathode and potassium electrolyte was
[PDF] in 1999.
The key difference between these works and the current one is that they at least in part relied on platinum in their cathodes. Platinum's downside? It is very expensive.
Both of these past studies and the current study consider potassium the "perfect" ion for the Prussian Blue cathode, as it's small enough to jump into and out of the loose lattice without damaging it.
Describes Mr. Wessells, "It fits perfectly – really, really nicely. Potassium will just zoom in and zoom out, so you can have an extremely high-power battery."
III. Uncertainty Remains
Potassium (-2.92 V) is the closest to lithium (-3.04) in standard potential voltage of the common battery chemistries [
]. Information on energy density and cell voltage versus discharge is not widely available, making it difficult, though, to compare the finished product.
The 1999 design showed a full charge voltage 2.0 V and a half charge voltage of 1.0 V. That's pretty bad compared to a standard discharge curve for a lithium ion cell that gives around 4.2 V at full charge and 3.8 V at half charge. But it's still to early to know what optimized commercial designs of potassium might be able to achieve.
That said, an early commercial version has been used to power
at least one mobile electronics device
A bit of a disclaimer on the most bold claim of 40,000 charge cycles, is that the battery was cycled at 17° C (62.6° F), much lower than car batteries or other designs operate at. The study admits:
Even at a very high cycling rate of 83
C, two thirds of its maximum discharge capacity is observed.
In other words, the "real world" operating efficiency after 40k cycles would likely fall somewhere between 66 and 83 percent.
The researchers also comment that their fancy new cathode must still be paired with a optimal anode (low voltage electrode) and an overall battery design in order to make the perfect potassium ion battery.
While the potential for portable electronics and EV/hybrid applications seems huge for this improved Potassium ion battery design, the authors are focused primarily on grid storage. Comments Mr. Wessells, "We decided we needed to develop a 'new chemistry' if we were going to make low-cost batteries and battery electrodes for the power grid. At a rate of several cycles per day, this electrode would have a good 30 years of useful life on the electrical grid."
is a hot field. With mankind
increasingly harvesting wind and solar energy
to produce electricity, utility companies are looking to battery banks as a potential solution to the variable nature of these power sources. Using battery grid storage consumers can be delivered alternative energy without interruption even when the wind isn't blowing and the sun isn't shining. However, given the already high costs of solar and wind power, finding cheap yet efficient solutions is as critical in the grid storage market as it is in the automotive and personal electronics markets.
[Image Source: Ames Power]
The new research was
[abstract] in the journal
"DailyTech is the best kept secret on the Internet." -- Larry Barber
Apple Aims to Build Solar Farm Near North Carolina Data Center
October 26, 2011, 9:42 AM
GM: Chevy Volt Owners Averaging 1,000 Miles Between Gas Stops
April 25, 2011, 12:25 PM
GM Looks to Reuse Spent Volt Batteries for Wind, Solar Power Storage
September 22, 2010, 11:26 AM
Tesla Motors Begins Production of All-electric Roadster
March 17, 2008, 8:04 PM
Debuted at CES 2017 - Corning Gorilla Glass Concept Car
January 7, 2017, 3:02 AM
Happy, healthy and feastive New Year to you and everyone in the world that about to celebrate the Season Holidays
January 1, 2017, 12:01 AM
In 2017, Here are the New Autos of 2018
December 30, 2016, 5:00 AM
What Happens When You Put a Blind Man in a Driverless Car?
December 14, 2016, 5:00 AM
Would You Like to Build Your Own BMW?
December 12, 2016, 5:00 AM
Jaguar I-PACE – Jaguar’s New Electric Concept / New SUV
November 16, 2016, 5:00 AM
Most Popular Articles
Kobo Aura One Vs Kindle Paperwhite
January 10, 2017, 1:21 AM
New at CES 2017 - Changhong 8K Super Slim TV 65ZHQ3R
January 8, 2017, 1:07 AM
OPPO R9 – The Smartphone with Excellent Camera and Long Battery Life
January 12, 2017, 12:01 AM
Are you in the market for a private antenna?
January 11, 2017, 12:01 AM
Comparison: Xiaomi Mi Mix Vs. HTC U Ultra
January 14, 2017, 12:10 AM
Latest Blog Posts
News of the Day
Jan 16, 2017, 12:10 PM
News and Technology Advancement
Jan 16, 2017, 7:58 AM
Jan 15, 2017, 12:32 AM
Here is Some News
Jan 14, 2017, 12:39 AM
News: Improved and New products
Jan 13, 2017, 12:01 AM
News around the world
Jan 12, 2017, 12:01 AM
Rumors and Announcements
Jan 11, 2017, 12:01 AM
This year CES and ridiculous gadgets
Jan 10, 2017, 12:01 AM
Nokia Android phone spurns the west.
Jan 9, 2017, 12:08 AM
New at CES 2017 - Changhong 8K Super Slim TV 65ZHQ3R
Jan 8, 2017, 1:07 AM
Debuted at CES 2017 - Vuzix Blade 3000 Smart Sunglasses
Jan 8, 2017, 12:39 AM
Some news of Day
Jan 7, 2017, 12:01 AM
News 2017 CES
Jan 6, 2017, 12:01 AM
Here is the Latest News in Tech
Jan 5, 2017, 1:47 AM
AI Beats World’s Best at Chinese board game “Go”
Jan 4, 2017, 11:21 AM
Las Vegas 2017 CES
Jan 3, 2017, 12:01 AM
News of Jan 2nd 2017
Jan 2, 2017, 4:40 AM
Wishing you all, the New Year brings the light of hope, joy, success, and Happy, Happy New Year.
Jan 1, 2017, 1:48 AM
More Blog Posts
Copyright 2017 DailyTech LLC. -
Terms, Conditions & Privacy Information