Thanks Ed, just some unconnected musings which may or may not be connected.
An email from Simon Savage dated 22/08/17;
Hi , while there is no doubt that graphene supercaps will take a lot of market share from Li-ion over the coming years, it is unlikely to happen over night... Li-ion batteries have been around for 25 years and only just now being introduced to mass-storage applications. I think the first applications we'll see supercaps used in will be smaller applications like medical devices and wearable technology, maybe in electric vehicles if someone throws enough research dollars at it. Even lead acid batteries are still being improved and market is growing, recently with solid state lead acid batteries.
So, its probably unlikely that the first application of a graphene supercapacitor will be in a 1MW system. Furthermore, i doubt that supercaps will directly replace Li-ion in these kind of applications , but rather there will be a period where supercaps and li-ion are used side-by-side in a hybrid system. My presentation to the Internet of Smart Materials Conference last week addressed this issue briefly: http://www.ionicindustries.com.au/wp-content/uploads/2017/08/Ionic-Industries-IoT-Conference-3.pdf
What is a solid-state battery? The benefits explained
A smaller, lighter battery could be a breakthrough for the electric vehicle industry
Electric cars and wearable technology need better batteries, but it’s believed current lithium-ion battery technology is near its full potential. Solid-state batteries are one of the leading alternatives.
In 2017, Toyota announced plans to have solid-state batteries in electric cars by 2020, while the Dyson electric car could also use solid-state battery technology developed by Sakti3 – a battery technology firm Dyson acquired in 2015.
Solid-state batteries replace the liquid or polymer electrolyte found in current lithium-ion batteries with a solid. The challenge, however, is in finding a solid material that is conductive enough to be used in large batteries. This is what the likes of Toyota and Sakti3 aim to solve.
A solid state energy storage device with supercapacitor–battery hybrid design
High power and high energy density are important requirements for advanced energy storage systems in mobile electronic devices, electric vehicles, and military-grade high-rate energy storage systems. However, achieving both high power and high energy in a single device is very challenging because high power density usually leads to a tradeoff with low energy density in devices that rely on a single ion storage mechanism. In this work, we designed a hybrid energy storage device consisting of an intercalative battery cathode and a capacitive supercapacitor anode. As a proof-of-concept, we used LiFePO4 (LFP) nanoparticles on an aluminum (Al) leaf current collector as the battery electrode and a free-standing reduced graphene oxide/carbon nanotube (RGO/CNT) nanocarbon membrane as the supercapacitor electrode. The hybrid device possesses outstanding features including (1) an asymmetric electrode configuration; (2) an ultra-lightweight current collector for the cathode; (3) a current collector free anode; (4) a quasi-solid-state gel polymer electrolyte. Compared with conventional supercapacitors and lithium-ion batteries, our hybrid device exhibits superior performance with both high energy density (180 W h kg−1) and high power density (218 W kg−1), and enhanced safety imparted by the quasi-solid-state gel electrolyte, representing one new direction for developing high-energy/high-power energy storage devices.
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