Electric vehicles have had a hard year. Sales have been disappointing. Former President Donald Trump has regularly disparaged them. And even many environmentally conscious car buyers have been choosing hybrids instead.

Yet the CEO of General Motors, Mary Barra, says the company is still committed to doing away with combustion engine cars in the United States by 2035 -- and she may have good reason for her optimism.

GM says it will start making money on battery-powered models by the end of the year -- becoming the only U.S. automaker aside from Tesla to achieve that feat. Sales of GM's electric vehicles are starting to take off. And the company just introduced a model that sells for less than $30,000 after a federal tax credit.

GM and other manufacturers have delayed investment in electric vehicle projects. But in an interview, Barra rebuffed the notion that the transition from internal combustion has run out of juice. She said GM was determined to uphold its 2021 pledge to phase out sales of gasoline cars by 2035 in the United States.

"That is the plan we're still executing," she said.

Her expression of resolve comes at a critical moment. Without GM, the largest U.S. carmaker, it is unlikely that the country can move away from internal combustion engines and the greenhouse gases they emit.

Barra's personal commitment to electric vehicles was on display late last year when problems manufacturing a key battery component stalled production.

Earlier in her career, all of it spent at GM, Barra oversaw all the company's production machinery. She drew on that expertise, spending "many days," she said, alongside engineers in a Detroit factory who were trying to fix an assembly line critical to battery manufacturing. Barra said she wanted to "understand the situation -- ask questions and then get them the support they needed."

Once that problem, which involved packaging battery cells into modules, was solved, GM swiftly increased production at battery factories in Spring Hill, Tennessee, and Warren, Ohio. Both those factories, and a third under construction in Lansing, Michigan, are part of a joint venture with LG Energy Solution of South Korea. GM is planning a fourth battery factory, in New Carlisle, Indiana, with Samsung, another Korean manufacturer.

GM has also locked in a steady domestic supply of lithium, a metal critical to batteries, by investing in a Nevada lithium mine called Thacker Pass.