The clean energy revolution is replacing oil and gas with a new global force: the minerals and metals needed in electric car batteries, solar panels and other forms of renewable energy.

Places like the Democratic Republic of Congo, which produces two-thirds of the world’s supply of cobalt, for example, are stepping into the kinds of roles once played by Saudi Arabia and other oil-rich nations. And a race between China and the United States to secure supplies could have far-reaching implications for the shared goal of protecting the planet.

An investigation by The New York Times drew on interviews with more than 100 people on three continents and thousands of pages of financial, diplomatic and other documents. Here are some of the findings.

The United States is vulnerable to price shocks and supply shortages as it embraces green energy.

The American government failed to safeguard decades of diplomatic and financial investments it had made in Congo, even as China was positioning itself to dominate the new electric vehicle era.

The sale, starting in 2016, of two major cobalt reserves in Congo by an American mining giant to a Chinese conglomerate marked the end of any major U.S. mining presence in cobalt in the country.

Chinese battery makers have forged agreements with the mining companies to secure steady supplies of the metal.

Beijing bankrolled a buying spree of mines in Congo, locking up a key supply chain.

As of last year, 15 of the 19 cobalt-producing mines in Congo were owned or financed by Chinese companies, according to a data analysis. The companies had received at least $12 billion in loans and other financing from state-backed institutions, and are likely to have drawn billions more.

The five biggest Chinese mining companies in Congo that focus on cobalt and copper mining also had lines of credit from Chinese state-backed banks totaling $124 billion.

One of the government-backed companies, China Molybdenum, which bought the two American-owned reserves, described itself to The Times as “a pure business entity” traded on two stock exchanges. Records show 25 percent of the company is owned by a local government in China.

Congolese officials accuse Chinese mining companies of cheating the country of promised revenues and improvements.

The Congolese are reviewing past mining contracts with financial help from the American government, part of a broader anti-corruption effort. They are also examining whether Chinese promises to build roads, schools, hospitals and other infrastructure were kept.

Separately, Chinese Molybdenum is being accused of withholding payments to the government at its Tenke Fungurume cobalt and copper mine. The company said it had done nothing wrong, and questioned if there was an organized effort to undermine it.

China has an idiom that goes something like: “Where there is a will to condemn, evidence will follow,” a spokesman said. “Vaguely I feel that we may be caught in the gaming of greater powers.”

The purchase by the Chinese of an American-owned mine was facilitated by a firm with Hunter Biden on the board.

Tenke Fungurume, one of the biggest cobalt mines in the world, was controlled by an American company, Freeport-McMoRan. Then it was sold in 2016 in a series of transactions worth $3.8 billion to China Molybdenum. The sale was aided by a Chinese private equity firm that bought out a minority owner in the mine.

A founding board member of the private equity firm was Hunter Biden, son of the American president. A Washington company that had been controlled by Mr. Biden remains a shareholder in the firm, according to Chinese financial documents. Chris Clark, a lawyer for Mr. Biden, said his client “no longer holds any interest, directly or indirectly,” in the Washington and Chinese firms. Filings in China show he is no longer a board member of the Chinese firm. Mr. Biden did not respond to requests for comment.

When asked if the president had been made aware of his son’s connection to the sale, a White House spokesman said, “No.”

Chinese ownership has increased the global supply of cobalt, but workers complain of safety lapses.

Increased mining and refining of cobalt by Chinese companies has helped meet the growing demand worldwide. But at least a dozen employees or contractors at the Tenke Fungurume mine told The Times that Chinese ownership had led to a drastic decline in safety and an increase in injuries, many of which were not reported to management.

The company said that the complaints were probably fabricated, and that it had actually increased safety.

The United States is behind in the race for minerals.

As the world pivots to a future focused on electric vehicles, the United States is playing catch-up, though both Congress and the Biden administration are now making first steps. Legislation passed the House on Friday that would provide more than a half-trillion dollars toward shifting the U.S. economy away from fossil fuels to renewable energy and electric cars.

Amos Hochstein, the State Department’s senior adviser for global energy security, predicts access to solar panels and electric vehicle batteries will determine energy security in the future.

“It’s a national security imperative that the United States ensure the 21st century doesn’t repeat the vulnerabilities of the 20th century,” he said.

Jay Last, a physicist who helped create the silicon chips that power the world’s computers, and who was among the eight entrepreneurs whose company laid the technical, financial and cultural foundation for Silicon Valley, died on Nov. 11 in Los Angeles. He was 92.

His death, in a hospital, was confirmed by his wife and only immediate survivor, Debbie.

Dr. Last was finishing a Ph.D. in physics at the Massachusetts Institute of Technology in 1956 when he was approached by William Shockley, who would share a Nobel Prize that same year for the invention of the transistor, the tiny electrical device that became the essential building block for the world’s computer chips. Dr. Shockley invited him to join a new effort to commercialize a silicon transistor at a lab near Palo Alto, Calif., about 30 miles south of San Francisco.

Dr. Last was awed by Dr. Shockley’s intelligence and reputation, but unsure about the job offer. Ultimately, he agreed to join the Shockley Semiconductor Laboratory because it sat in the Northern California valley where he had spent a summer harvesting fruit after hitchhiking there from his home in Pennsylvania steel country.

But he and seven of his collaborators at the lab clashed with Dr. Shockley, who later became infamous for his theory that Black people were genetically inferior in intelligence to white people. They quickly left the lab to create their own transistor company. They later came to be called “the traitorous eight,” and their company, Fairchild Semiconductor, is now seen as ground zero for what became known as Silicon Valley.

At Fairchild, Dr. Last led a team of scientists who developed a fundamental technique that is still used to manufacture computer chips, providing the digital brains for billions upon billions of computers, tablets, smartphones and smartwatches.

“There was nothing more important than Fairchild Semiconductor to the Silicon Valley experience as we know it today,” said David C. Brock, a curator and director of the Software History Center at the Computer History Museum in Mountain View, Calif. “Many of the dynamics that still persist were crystallized by the founders of Fairchild, and Jay was right in the middle of it.”

Jay Taylor Last was born on Oct. 18, 1929, in Butler, Pa. His father, Frank, a German immigrant, and his Scotch-Irish mother, Sarah, had met when they were two of the three teachers at a high school in Ohio. After they married, Frank Last felt he could not support a family on a teacher’s salary, so they moved to Pennsylvania, where he went to work in the new Butler steel mill, not far from Pittsburgh.

Jay Last grew up in Butler before making his first pilgrimage to the West Coast when he was 16. With the blessing of his parents — and carrying a letter from the local police chief saying he was not running away from home — he hitchhiked to San Jose, Calif., which was then a small farming town. He had planned on making a little money picking fruit, but he arrived before the harvest began.

Until it did, he lived, as he often recalled in later years, on a nickel’s worth of carrots a day. Whenever he faced a difficult situation, he said in an interview for the Chemical Heritage Foundation (now the Science History Institute) in 2004, he told himself, “I got through that when I was 16, and this is not that bad a problem.”

At the suggestion of his father, he soon enrolled at the University of Rochester in New York State to study optics — the physics of light. During summers back home in Pennsylvania, he worked at a research lab that served local plate-glass manufacturers.

Fulfilling a promise he had made to himself as a teenager, he went on to get his doctorate at M.I.T., before returning to Northern California and joining the Shockley lab. But he chafed at Dr. Shockley’s overly attentive and controlling style of management.

“I was a laboratory assistant, and that’s the way he was working with everybody,” he remembered in 2004. “There was no such thing as everybody getting together in a seminar and discussing what we were doing.” After about a year, he and his colleagues left to form Fairchild Semiconductor.

Using materials like silicon and germanium, Dr. Shockley and two other scientists had shown how to build the tiny transistors that would one day be used to store and move information in the form of an electrical signal. The question was how to connect them together to form a larger machine.

After using chemical compounds to etch the transistors into a sheet of silicon, Dr. Last and his colleagues could have cut each one from the sheet and connected them with individual wires, much like any other electrical device. But this was enormously difficult, inefficient and expensive.

One of the founders of Fairchild, Robert Noyce, suggested an alternative method, and this was realized by a team Dr. Last oversaw. They developed a way of building both the transistors and the wires into the same sheet of silicon.

This method is still used to build silicon chips, whose transistors are now exponentially smaller than those manufactured in the 1960s, in accordance with Moore’s Law, the famous maxim laid down by another Fairchild founder, Gordon Moore.

With Dr. Last’s death, Dr. Moore is the last surviving member of the “traitorous eight.”

The leaders of Fairchild Semiconductor would go on to build several other chip companies, including Intel, co-founded by Dr. Moore, and Amelco, co-founded by Dr. Last. The company’s founders and employees would also create some of the leading Silicon Valley venture capital firms and personally invest, as Dr. Last did, in many of the companies that sprouted up in the region over the decades.

Dr. Last retired from the chip business in 1974 and spent the rest of his life as an investor, an art collector, a writer and an amateur mountain climber. His collection of African art was donated to the Fowler Museum at the University of California, Los Angeles, and his trove of California citrus-box labels — an echo of his teenage summer in Northern California — is now at the Huntington Library, Art Museum and Botanical Gardens in San Marino, Calif.

As Dr. Last was finishing his Ph.D. in 1956, he was asked to take over as head of the glass lab back in Butler, Pa., where he had worked during the summers. It seemed like a promising opportunity.

“I went and told my parents,” he remembered. “My mother said, ‘Jay, you can do a lot better than that with your life.’”