The investment will give Rio about 4.9% of the company.
The two have also formed a strategic partnership under which Rio will collaborate on battery metals as inputs for Nano One's cathode process technologies.
The partnership and funding will accelerate Nano One's multi-cathode (multi-CAM) commercialisation strategy and support cathode active materials (CAM) manufacturing in Canada for a cleaner and more efficient battery supply chain for North American and overseas markets.
"The global transition to a low-carbon electrified economy will require millions of tonnes of battery materials, so it is critically important to produce these materials efficiently and with the lowest environmental footprint," Nano One CEO Dan Blondal said.
"Rio Tinto brings deep experience in high volume production and technology commercialisation, as well as a growing battery metals business. We are excited to be partnering with Rio Tinto, our shared vision will see many opportunities for collaboration as we drive for change."
The partnership will include a study of Rio's battery metal products, including iron powders from its Fer et Titane facility in Quebec, as feedstock for the production of Nano One's cathode materials.
Rio will contribute know-how from its Critical Minerals and Technology Centre, which has developed a unique expertise in the extraction and processing of critical minerals such as lithium and scandium, as well as minerals from Canada, the US, and other international sources to further drive localisation of the lithium-ion battery value chain.
"Localised, clean and secure supply chains are critical for the success of the energy transition that is now underway and this requires partnerships with innovative companies like Nano One to help us differentiate, disrupt and accelerate the path to a net-zero future," Rio managing director of battery materials Marnie Finlayson said.