27. Chemical stability of LPS sulfide solid electrolytes : problems in paradise?

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Gasteiger paper on LPS stability with PEO – 2019

LPS and LLZO inorganic solid electrolytes have been the workhorse of solid battery efforts for the past 20 years. LPS (or sulfur based) solid electrolytes have a lithium ion conductivity higher than liquid electrolytes and are softer and easier to process into separators than LLZO. However, their electrochemical stability is quite narrow on the anode as well as on the cathode side which require protective coatings for compatibility. One common method to interface high conductivity LPS with metallic lithium anode is to use a PEO polymer interface between the reactive lithium anode and the LPS solid electrolyte separator. In this podcast i discuss the stability of LPS with the PEO membrane.

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26. The (only) Tesla battery cell patent

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The Tesla patent
Fast charging

Tesla patent link

Arguably the most successful electric car company in the world has (arguably) the fewest battery cell patents: 1. Tesla’s business model so far has not included cell chemistry development. The only patent they claim (in 2019) comes from the Jeff Dahn group and focuses on additives for fast charge and long lifetime of commercial cells. Listen to my podcast to learn more.

25. The dry electrode process of Maxwell Technologies (soon to be Tesla owned)

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Dry electrode process from Maxwell Technologies

Patent 20170098826A1

Capacitor cycle life and operating voltage are governed by the lack of impurities left over from the electrode casting process. Maxwell Technologies claims a solvent – less, dry process can double the cycle life of their capacitors. In this podcast I also discuss the viability of this dry process for manufacturing battery electrodes.

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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!

23. Cobalt free cathodes: Jeff Dahn (now with Tesla) suggests they are possible and stable

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Cobalt free cathodes

Jeff Dahn paper

The first high voltage cathodes were proposed by John Goodenough in the form of LCO (lithium cobalt oxide) and they were quickly adopted as commercial materials. In an effort to lower costs (cobalt is expensive), analogous LNO (lithium nickel oxide) cathodes have recently been commercialized as doped NCM (nickel, cobalt, manganese) and NCA (nickel, cobalt, aluminum) cathodes. Modern NCM/NCA contain only 5% cobalt and cobalt free derivatives may soon become a reality. Learn how and why in this podcast.

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.