Noon Energy was founded in 2018 by Chris Graves after working on a tool for NASA’s Perseverance Mars rover that snatches carbon dioxide out of the red planet’s atmosphere and converts it into oxygen. Using this same principle, thes process has been tweaked to store energy for longer periods of time than what’s commercially viable with today’s lithium-ion batteries.

Noon Energy is building the first carbon-oxide battery. It will be able to deliver a desired amount of capacity (determined by the customer’s needs) for 100 hours or more, affordably. Noon has already build a prototype at lab scale, the next big goal is to build demonstration projects to test the technology in the field.

By 2023, Noon Energy had raised a total of $31.2M in funding over 4 rounds: a Grant round, a Non-equity Assistance round, a Seed round and a venture round (Series A). Their latest funding was raised on Dec 14, 2022, amco Ventures and Clean Energy Ventures are the most recent investors.

The Noon Energy team successfully scaled up a lab prototype’s storage capacity by a factor of 50 during 2021-2022, which gave them confidence that the core technology will work at the scale of a grid power plant. With that in hand, the company raised $28 million Series A financing announced on Jan 2023. It had previously raised a $3 million seed round while remaining coy about what its technology entailed.

Clean Energy Ventures led the new round with Aramco Ventures’ Sustainability Fund. Other investors included Emerson Collective, At One Ventures, Mistletoe and Doral Energy-Tech Ventures.

Their battery based on elements as simple as carbon and oxygen. When the battery is fully discharged, the CO₂ tank is filled with 93% CO₂ and 7% CO at 200 bar. The gasses are stored at a temperature of 34 ºC. The battery maintains a high temperature between 600 and 800 ºC.

When a voltage of 1.08 V is applied during charging, CO₂ from the tank enters the negative electrode. CO₂ is electrochemically reduced in the porous negative electrode, forming CO and oxygen ions (O²⁻). CO diffuses to the nearby zirconia support loaded with nickel nanoparticle catalysts, where it is thermochemically reduced to solid carbon nanofibers or multi-walled carbon nanotubes and CO₂. CO₂ diffuses back to the negative electrode for electrochemical reaction. The net reaction in the negative electrode is CO₂(g) + 4e⁻ → C(s) + 2O²⁻. Oxygen ions diffuse through the electrolyte layer to the positive electrode and are oxidized to O₂.

The CO reduction at zirconia support is exothermic. Heat released from this reaction can be absorbed by the CO₂ electrolysis reaction in the negative electrode and oxygen ion oxidation in the positive electrode. Both reactions are endothermic. Reaction heat can easily transfer from the zirconia support to the positive electrode because the electrolyte layer is very thin (no more than 100 microns).

During charging, the consumption of CO₂ forms a concentration gradient between the negative electrode and the CO₂ tank, causing CO₂ to flow into the negative electrode. The production of O₂ generates a concentration gradient between the positive electrode and the balloon, causing O₂ to flow into the balloon. Thereby during charging, the CO₂ pressure decreases and the O₂ pressure increases. The combined storage arrangement allows the volume of the CO₂ tank to vary with an inflatable balloon of O₂ inside the CO₂ tank, resulting in an automatic flow of reactants and products within the system without the need of pressure regulating means.

The company is not selling any batteries at the moment, but as most battery providers, the assumption is they will be selling their batteries per kWh depending also on the scale of the storage project.

Noon Energy has developed a novel carbon-based battery that does not store energy in metals, a significant advantage over battery technologies used today. Instead, it stores energy in carbon and oxygen using nature-based chemistry principles, eliminating the need for hard-to-mine metals including lithium and cobalt, and it requires only 1% of other critical elements compared to lithium-ion batteries. Other innovations that lead to successful lab pilots are:

• Thermal insulation The battery is operated at high pressures and temperatures ranging from 50 to 200 bar and 600 to 800 ºC, respectively, to permit efficient chemical reactions in electrodes and high ionic migration within the electrolyte layer. The thermal insulation maintains the battery temperature and improves its energy efficiency.

• Porous negative electrode During charging, the porous negative electrode reduces CO₂. It is permeable to CO₂ gas diffusion. The electrode contains a catalyst material, such as doped ceria (CeO₂), which catalyzes exclusively the reduction of CO₂ to carbon monoxide (CO) and oxygen ions (O²⁻). The decomposition of CO into solid carbon nanofibers or multi-walled carbon nanotubes occurs on the second catalytic material, such as nickel nanoparticles, loaded on a nearby zirconia support. The zirconia support improves the thermal stability of nickel nanoparticles. The surface of catalysts is coated with molten lithium carbonate (Li₂CO₃) to improve robustness for reversible carbon deposition. During reversible deposition cycles, the mobility of the molten phase also helps maintain the wetting of the catalyst and carbon. The surface coating of molten carbonate also accelerates the reactions.

• Solid electrolyte layer The electrolyte allows fast oxygen ion migration at high temperature. The thickness of the electrolyte layer is between 10 and 100 microns. The electrolyte is made of solid oxide oxygen ion conductors, molten metal carbonates, molten hydroxides, or solid oxide proton conductors.

• Porous positive electrode During charging, the porous positive electrode oxidizes oxygen ions to O₂. It is permeable to O₂ diffusion. The positive electrode comprises a catalyst for promoting O₂ formation.

• Heat exchanger During charge mode, the heat exchanger heats the cold CO₂ flowing from CO₂ tank towards the negative electrode with hot O₂ flowing away from the positive electrode .

• Storage arrangements The storage arrangement comprises a tank for storing CO₂ reactant and an inflatable balloon inside the tank for storing O₂ products. The CO₂ tank and O₂ balloon are connected via valves to the battery’s negative and positive electrodes, respectively. Thus, the battery and storage arrangements form a closed system that enables a gaseous flow from the CO₂ storage and to the O₂ storage during the charging process, while maintaining constant total pressure and volume of the gaseous reactant (CO₂) and product (O₂).

Noon Energy is building the first carbon-oxide battery, enabling grid-scale long-duration energy storage (LDES), meaning it will be able to discharge energy continuously for more than 100 hours. Day-storage is a market that has yet to be unlocked by emerging battery chemistries.