AIM-listed tech group CAP-XX almost doubled in market value on Wednesday after the launch of Thinline, the world's thinning supercapacitor.Thinline has been released to address the space-constrained needs of new products developed for the Internet of Things (IoT), CAP-XX said.The product is designed for use in ultra-thin electronic devices, such as wearable fitness monitors and smart watches.The stock was up 90.2% at 2.9p near the end of trade, giving CAP-XX a market cap of £7m.