Electric-vehicle makers and suppliers rallied on Tuesday after a string of positive news for the industry, with Chinese companies clocking in the biggest gains. U.S.-traded shares of Nio Inc. and XPeng Inc. surged after the two Chinese EV makers reported strong sales for May and Citigroup Inc. boosted its estimates for the industry. The optimism also lifted peers Workhorse Group Inc. , Nikola Corp. , Lordstown Motors Corp. and Fisker Inc. , with SNE Research saying global EV battery sales have more than doubled in the first four months of the year. Electric-car makers have had a hard time this year to hold on to the intense market enthusiasm of 2020 amid an increasing threat of competition from legacy automakers, the global semiconductor shortage and a rising reluctance among investors for holding onto riskier assets. […]