When Donut Lab first announced its solid-state battery earlier this year, there was some speculation around whether the Finnish startup had actually produced a supercapacitor, which is a much shorter-term form of electrical storage. Supercapacitors can charge and discharge quickly, similar to Donut Lab's claimed solid-state battery. But supercapacitors are totally different from batteries in terms of energy storage capacity and long-term use. Was Donut Lab's battery actually just a supercapacitor in disguise? The startup says no, and it has the independent test results to prove it. The test, which was yet again conducted by state-owned VTT … Read the full story at The Verge.