STOCKHOLM (Reuters) -U.S. battery startup Lyten has agreed to buy most of bankrupt Swedish battery maker Northvolt, it said on Thursday, potentially offering a way back for the European company that was once seen as the region's answer to rivals in Asia.

Lyten, a Silicon Valley battery startup developing lithium-sulphur cells as a cleaner alternative to lithium-ion, is backed by Jeep-owner Stellantis and U.S. delivery services provider FedEx.

The deal revives hopes for European battery independence after Northvolt - the continent's potential rival to major Chinese electric vehicle battery makers - filed for bankruptcy in March, making it one of Sweden's largest corporate failures, with a frantic push to find a buyer.

"Our plans are... in large part to pick up where the Northvolt team left off," Lyten CEO Dan Cook told Reuters, declining to disclose the purchase price beyond saying it was at a "substantial discount" to the original asset value.

Northvolt has received much criticism that the company overpromised while failing to deliver battery cells deemed good enough quality for clients, even with help from its biggest customer, truckmaker Scania.

Lyten hopes to restart the flagship Skelleftea plant in northern Sweden and resume deliveries of lithium-ion battery cells in 2026. It acquired Northvolt's energy storage business in Poland in July, Europe's largest, and is targeting automotive, defence and energy storage markets.

Cook said several of Northvolt's former management would be joining Lyten, though not founder and ex-CEO Peter Carlsson.

"We are focused on developing to be the leaders in locally sourced, locally manufactured batteries for both the North American and European markets right now," he said.

Lyten said in July that it had secured over $200 million in additional equity investment to support its acquisitions and expansion plans.

Cook said Lyten would prove its worth to Northvolt's former customers by focusing first on providing high yields to a single customer. Northvolt's order book once totaled over $50 billion from automakers such as BMW, Volkswagen and Audi.

"We actually think they'll come back, perhaps quicker than people believe," said Cook, Leyton's co-founder.

The deal includes Northvolt's projects in Sweden and Germany, as well as its intellectual property. Work was also underway to acquire its Canadian unit.

Before its collapse, Northvolt expanded across the Atlantic but later refocused on Sweden as its financial crisis deepened, selling assets for nominal sums.

(Reporting by Marie Mannes and Alessandro Parodi; Editing by Adam Jourdan and Emelia Sithole-Matarise)