There are Solid State Battery
There are Solid State Battery (SSB) companies more advanced & farther ahead than Quantumscape. Solid Power out of Colorado, for instance, will deliver 100 Ah EV sized batteries to its auto partners Ford & BMW in early 2022 for automotive qualification testing. And in terms of "investing" as the author noted, Solid Power trades under the ticker DCRC and it only about 1/8 the valuation of QuantumScape (ticker QS).