Shares of electric car-maker Tesla and mobile carrier China Unicom climbed in Friday trading after the companies said they are partnering to build charging stations across China. Tesla said it will build 400 charging points at China Unicom retail outlets in 120 cities. In addition, Tesla will build 20 supercharging stations, which are able to charge vehicles up to 16 times more quickly, at China Unicom stores in 20 cities. Tesla said all charging points will be free for for its customers. Tesla said the agreement will accelerate Tesla's charging network in the country and deepen its pre-existing cooperation with China Unicom.