This is a very interesting ongoing debate. Both the technical applications (as here) are debated, and the economics. With rapidly falling new battery costs, there is a question as to whether second-life batteries will really be cheaper than new. Clearly though, the auto manufacturers, Nissan and BMW in particular are investing heavily in second-life EV batteries for stationary storage.

The article makes an interesting point though that can't be ignored. Recycling.  Using second-life batteries at best delay the need for the battery to be recycled. If there is no market for them then that brings the issue forward significantly.  Let's hope there is also significant R&D spend, and investment in creating a viable and easy Lithium battery recycling capability and capacity.