A Lithium-Ion battery typically has the following elements:
- A Lithium metal oxide cathode
- A liquid or gel electrolyte to transport ions
- A thin plastic separator
- A Lithium carbon (graphite) anode
The electrolyte transports positively charged ions through the separator, transferring charge from the cathode to the anode.
In a solid-state battery, the electrolyte is replaced with a solid material that performs the functions of both the electrolyte and separator, and the graphite anode is replaced with much lighter lithium metal.
Solid-state lithium batteries offer major benefits in power-to-weight density and safety, with low fire risk.
There are three main solid-state electrolyte technologies:
- Sulphides are excellent conductors but react with moisture in the air and release hydrogen sulphide gas raising safety issues.
- Ceramic Oxide separators are stable, safe, and non-flammable, but ceramics are brittle, and the thin sheets are difficult to manufacture on an industrial scale.
- Polymers are easy to manufacture but conduct properly only when warm, so they require heating.
There are further challenges that are common to all three technologies:
- Lithium metal plates grow dendrites that can penetrate even a solid-state electrolyte and degrade the battery over time.
- Any unevenness in the contact surface between two solid materials increases the resistance compared to contact with a liquid.
- Cells physically swell and shrink as they charge and discharge. Liquids can absorb this, but solid-state cells need constant mechanical pressure to prevent bulging.
Conclusion
Solid-state lithium batteries offer major advantages in battery weight, range, charging times, and fire safety. However, they face several challenges, and mainstream adoption is unlikely before 2030.
Colin Twiggs is a former investment banker with almost 40 years of experience in financial markets. He founded PVT Capital (AFSL number 546090), which provides income and growth strategies to wholesale clients.
Colin also co-founded Incredible Charts and writes the popular Patient Investor newsletter.
Using a top-down approach, Colin identifies macro trends in the global economy and then combines fundamental and technical analysis to evaluate opportunities in sectors that stand to benefit.
Focusing on interest rates and financial market liquidity as primary drivers of the economic cycle, he warned of the 2008/2009 and 2020 bear markets well ahead of actual events.