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24. The “R&D” development cycle : the good, the bad and the ugly

Key elements of a successful battery R&D program

I receive a lot of interest regarding setting up R&D programs for lithium ion batteries. In this podcast I dissect the defining elements of a successful battery R&D program. If your company is interested in this type of venture or if you are a student entering this field at an early stage, you may find this episode more interesting than my typical podcast. Enjoy!

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22. Ni rich NCM (cathodes): how we got it, why we use it and how to keep it stable

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Recent twist in the capacity fade mechanism of Ni rich NMC

NCM622 capacity fade paper from Brookhaven National Lab

Currently accepted cathode dogma preaches the root cause of capacity fade in Ni rich NMC is the irreversible phase change of the active material crystalline structure. However, recent findings challenge the status quo. Listen to my podcast to learn more.

20. Stable lithium plating with 3x capacity of commercial Li-ion cells… apparently possible @Stanford

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Stable cycling of lithium metal anodes

Paper link

Yi Cui’s web page

Past podcast on lithium ion separators

The Holy Grail of anodes is a lithium metal anode. Taming this temperamental beast has been unsuccessful so far, but it is bound to change. In this podcast I discuss a composite separator membrane which enables plating lithium with 3x the speed and 3x the quantity (capacity) of commercial lithium ion cells.

19. Can we bypass the energy – fast charge compromise?

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How to break a compromise

Fast charge is limited by the reduction (lithiation) potential and nature of the anode. If charged too fast, graphite anodes may be plated with lithium metal because their lithiation potential is too close to the plating potential of lithium. Faster charge can be accomplished with anodes which lithiate at higher potentials (such as NTO). The trade-off is lower cell energy since there will be a smaller voltage difference between anode and cathode. However, there are anode materials which may bypass this energy – fast charge compromise. Listen to my podcast to learn more.

17. How fast can commercial cells really charge?

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Energy cells vs. power cells – charging rate

Belharouk et al, 2018, Electrochemical Communications – charging limits of NCM811 cathodes and graphite anodes

Bhagat et al, 2018, Electrochimica Acta – charging limits of commercial energy cell

Miller et al, 2017, SAE – charging limits of commercial power cell

In this podcast I discuss the charging rate limits for commercial electrode materials as well as commercial cells. They are faster than you may think.

16. 2 minute charge? Impossible!

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Patent application

Bruce Dunn

This material can charge in 2.5 minutes, > 10,000x.

Currently commercial lithium ion batteries typically charge in 1.5 – 2 hours. ‘Fast charge’ is limited to 30 – 45 minutes and with harsh consequences on cycle life and safety. However, there are battery electrode materials which blur the capacitor/battery line. MoS2 has been claimed by professor Dunn (UCLA) to be such a “pseudocapacitor”. This podcast discusses a patent claiming a pseudocapacitor electrode material which can charge in 2.5 minutes for > 10,000x and with a capacity > 120mAh/g.

> 10,000 cycles with no capacity fade at a charge/discharge rate of 23C (which corresponds to 2.5 minute charge). Capacity is stable > 120 mAh/g.

15. Amprius: silicon anodes by CVD

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Amprius grows silicon directly off current collectors by CVD

Patent

Amprius website

Yi Cui – Stanford

Growing silicon directly off current collectors (by CVD) offers a rich library of strategies to solve traditional problems associated with silicon anodes. However, it also raises a few new ones. Find out more in my latest podcast.

Silicon active material (340) is grown onto nickel silicide template (310) and may be coated by carbon or lithium conducting shell (330). The silicide template is hard rooted onto the copper current collector (320) for enhanced electron conductivity.

14. 1D Silicon anodes from Sila Nanotechnologies

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Why is BMW investing in this company?

2017 Sila US9673448

Professor Gleb Yushin’s page

Sila Nanotechnology

Secondary particle of Sila’s silicon anode depicting the 1D carbon whiskers for electron conductivity and the silicon nanoparticles for lithium capacity

Anodes with silicon active materials may offer more than 2x the capacity of anodes with graphite active materials and improved rates of operation due to a low risk of lithium plating. A 1D architecture consists of ultrathin wires or whiskers as opposed to ultrathin sheets (2D). Emerging from the lab of professor Gleb Yushin, Sila Nanotechnologies focuses on such electron conductive wires (carbon based) decorated with silicon nanoparticles. This concept provides a highly porous secondary structure where the silicon particles have room to expand and contract without cracking the overall anode structure and is claimed to work well with liquid electrolyte systems. This podcast dissects a 2018 patent which claims Sila’s core silicon anode technology.