Last December IEEE Spectrum highlighted new findings published by researchers at Stanford. They show it should be possible to create 'lithium rich' electrodes which would increase Li battery energy capacity by 50%. The author illustrated the increase using the Tesla P100D pack. It's interesting that this scale of capacity increase seems about what people think would be needed by Semi in order for it's specs to be met while weight and cost are consistent with announced purchase prices.
I'll note that Jeffrey Dahn and his battery research team pretty much specialize in understanding "the way atoms rearrange themselves in the electrode when it’s being charged and how electrons are stored in the battery’s atomic and chemical structures." and modifying those structures to improve performance. They are able to test and evaluate how new formulations will retain charging capacity over tens of thousands of cycles in weeks rather than years, using custom testing equipment they've developed and used the past several years.
While there is no way to know if this is the avenue Tesla may have taken to greatly reduce battery costs for Semi and other new products,
I think this shows that it is possible for there to be very major performance increases going forward, not only the incremental 7 - 8 percent annual increases everyone expects based on progress rate over the last ten years.
New Analysis of Lithium-Ion Batteries Shows How to Pack in More Energy
"If electric vehicles are ever going to outcompete gas-powered ones, batteries must improve. Conventional lithium-ion batteries, the most energy-dense for their weight, can only be charged to about 50 percent of their theoretical capacity. When researchers have tried to pack more lithium into a battery’s electrodes, it hasn’t helped. The electrodes begin to quickly degrade after the first discharge/recharge cycle, and nobody has been able to figure out how to prevent it.
Now there’s a clue. Using a combination of theoretical computer modeling and sophisticated X-ray methods, researchers have for the first time found a relationship between the way atoms rearrange themselves in the electrode when it’s being charged and how electrons are stored in the battery’s atomic and chemical structures. This insight should give battery-makers a blueprint for building lithium-rich electrodes that could dramatically improve battery performance.
At its full potential, a lithium-rich battery could improve the range of today’s electric vehicles by a third or better. A Tesla Model S with the company’s P100D battery pack, for instance, could go from traveling 315 miles (about 500 kilometers) on a single charge to as far as 473 miles. Or the carmaker could keep the range at 315 miles, but lower the price to compete with gas-powered vehicles without a rebate."
