In 1954, he graduated from Peking University with a degree in philosophy and worked throughout his life at research institutes around the world, including in Paris and Beijing. 

In 2010, the academic made his last wishes public in an interview with the Chinese publication Southern People Weekly. 

Shortly before his 80th birthday, he said: "I will leave my brain frozen. Take it out after 300 or 500 years. Some people want to be resurrected in this way, but I don't think resurrection is possible. I am trying to prove my theory of precipitation, whether culture affects the brain and whether it is possible to find remnants of Chinese culture in my brain after a few hundred years."

Li was referring to a theory he developed in the 1960s, which argued that exposure to history and culture can leave traces in the physical structure of the brain. 

In 2020, before Li's 90th birthday, he told the same magazine that he had donated $80,000 to a foundation that freezes human remains.

He said he wanted his brain to be "preserved for as long as possible until brain science is sufficiently advanced", adding that he knew there was a "95 percent chance that this wish will not come true".

Li's relatives, including his friends, said they were skeptical about what might come from Li's brain because what he wanted went against the traditional Chinese belief that "the bodily integrity of corpses should be preserved."

Li's brain was frozen by the Arizona-based Alcor Life Extension Foundation, a non-profit organization specializing in the cryopreservation of human remains.