MILAN, June 19 (Reuters) - Automaker Stellantis

holds a 9.5% stake in U.S. solid-state battery startup Factorial

Energy ( FAC ) and might buy further shares in the future, a SEC

filing showed.

Solid-state batteries for electric vehicles are expected to

be lighter, with better energy density than, traditional

lithium-ion batteries, and ensuring faster charging times.

However manufacturers have so far struggled to produce them at

scale.

* Stellantis' ( STLA ) overall stake in Factorial is valued around

$126 million at current stock prices.

* Stellantis ( STLA ) sees Factorial as an "attractive investment

opportunity", the filing showed.

* The Franco Italian automaker first invested in Factorial

in 2021, with a €75 million ($86 million) deal.

* Stellantis ( STLA ) said earlier this month it had integrated

Factorial's 'FEST' solid-state battery cells into a development

vehicle and launched a road-testing program to verify

performance, safety and reliability.

* According to the filing, Stellantis' ( STLA ) Financial Services

CEO Jon Nelson has been elected to Factorial's board.

($1 = 0.8728 euros)