Sigma Lithium Resources Corp. Chief Executive Calvyn Gardner has said his Brazilian start-up and Ganfeng Lithium Co. Ltd are negotiating a deal to supply the Chinese maker of batteries with lithium, Reuters reports.

The news agency quotes Mr Gardner as saying in an interview that US maker of electric vehicles Tesla Inc., a customer of Ganfeng Lithium, asked the companies to do a deal.

Mr Gardner said a deal is far off, however, in part because Ganfeng Lithium wishes Sigma Lithium Resources to export its lithium only to China.

The report says Sigma Lithium Resources has a licence to mine hard-rock lithium in the southeastern Brazilian state of Minas Gerais.

The start-up is also planning a plant for processing lithium, Reuters says.