Thermochemical Approaches to Carbon Dioxide Capture and Energy Storage

Thermochemical approaches exploit reversible chemical reactions to capture carbon dioxide and store or release energy at high temperatures. Central to these methods are looping cycles in which a solid sorbent alternately reacts with CO₂ (carbonation) and releases it upon heating (calcination). Calcium-based looping, using CaO/CaCO₃, is the most mature example, offering integration with power plants, industrial furnaces and waste heat streams. Beyond calcium, mixed metal oxides and perovskite materials enable tailored heat effects and redox activity, permitting isothermal operation and reduced energy penalties. Chemical looping schemes extend this concept by using metal oxides to transfer oxygen between fuel and combustion zones, intrinsically generating a pure CO₂ stream. In sorption-enhanced reforming, catalysts and sorbents are co-located to simultaneously convert hydrocarbons or biomass into hydrogen while capturing CO₂, thus intensifying reaction pathways and reducing downstream separation costs. Thermochemical energy storage leverages reversible gas-solid reactions—often involving water or CO₂—to store surplus renewable heat and deliver it on demand. Across these technologies, advances in material design, reactor engineering and process integration aim to minimise energy losses, improve sorbent life and enable cost-effective deployment in power, hydrogen and industrial sectors. Collectively, thermochemical routes offer a versatile platform for deep decarbonisation and renewable heat management at industrial scale.

Research from Nature Portfolio

Recent studies have demonstrated the synthesis of hollow, MgO-stabilised CaO microspheres with multishelled porosity, achieving up to fivefold higher CO₂ uptake over limestone references and stable performance across more than 30 carbonation–calcination cycles. Detailed microscopy and compositional analyses have revealed that uniform MgO distribution and open pore networks are key to suppressing sintering and preserving reactive surface area. Another seminal contribution has explored calcium looping for steel mill decarbonisation, proposing in-plant lime production cycles that leverage waste heat and standard kiln infrastructure. This concept can deliver the sector’s mid- and long-term CO₂ reduction targets several decades ahead of schedule, with avoidance costs lower than prevailing emission trading prices. Both lines of work underscore the importance of material stabilisation and process synergy in achieving economically viable industrial carbon capture.

Thermochemical Approaches to Carbon Dioxide Capture and Energy Storage publication trend

The graph below shows the total number of articles in thermochemical approaches to carbon dioxide capture and energy storage across all publications each year (not limited to Nature Index journals).

Technical terms

Carbonation: Exothermic reaction in which a metal oxide reacts with CO₂ to form a carbonate.

Calcination: Endothermic thermal treatment that decomposes a carbonate back into oxide and releases CO₂.

Looping cycle: Repeated sequence of carbonation and calcination to capture and regenerate sorbents.

Chemical looping: Process using a metal oxide to transfer oxygen for combustion, yielding concentrated CO₂.

Sorption-enhanced reforming: Integration of catalytic fuel conversion with in situ CO₂ capture to drive reactions forward.

Thermochemical energy storage: Storage of heat via reversible chemical reactions for later release at elevated temperatures.

References

1. A review of developments in pilot-plant testing and modelling of calcium looping process for CO 2 capture from power generation systems. Energy & Environmental Science (2015).
2. High-throughput design of complex oxides as isothermal, redox-activated CO 2 sorbents for green hydrogen generation. Energy & Environmental Science (2024).
3. Optimization of the structural characteristics of CaO and its effective stabilization yield high-capacity CO2 sorbents. Nature Communications (2018).
4. Inherent potential of steelmaking to contribute to decarbonisation targets via industrial carbon capture and storage. Nature Communications (2018).
5. Sorption-enhanced Steam Methane Reforming for Combined CO2 Capture and Hydrogen Production: A State-of-the-Art Review. Carbon Capture Science & Technology (2021).
6. Design of a MW-scale thermo-chemical energy storage reactor. Energy Reports (2018).
7. Kinetics of Solid-Gas Reactions and Their Application to Carbonate Looping Systems. Energies (2019).