Carbon capture and storage (CCS) is broadly recognised as having the potential to play a key role in meeting climate change targets, delivering low carbon heat and power, decarbonising industry and, more recently, its ability to facilitate the net removal of CO2 from the atmosphere. However, despite this broad consensus and its technical maturity, CCS has not yet been deployed on a scale commensurate with the ambitions articulated a decade ago. Thus, in this paper we review the current state-of-the-art of CO2 capture, transport, utilisation and storage from a multi-scale perspective, moving from the global to molecular scales. In light of the COP21 commitments to limit warming to less than 2 °C, we extend the remit of this study to include the key negative emissions technologies (NETs) of bioenergy with CCS (BECCS), and direct air capture (DAC). Cognisant of the non-technical barriers to deploying CCS, we reflect on recent experience from the UK's CCS commercialisation programme and consider the commercial and political barriers to the large-scale deployment of CCS. In all areas, we focus on identifying and clearly articulating the key research challenges that could usefully be addressed in the coming decade.

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Carbon capture and storage (CCS): the way forward

Ionic liquids (ILs) are liquids consisting entirely of ions and can be further defined as molten salts having melting points lower than 100 °C. One of the most important research areas for IL utilization is undoubtedly their energy application, especially for energy storage and conversion materials and devices, because there is a continuously increasing demand for clean and sustainable energy. In this article, various application of ILs are reviewed by focusing on their use as electrolyte materials for Li/Na ion batteries, Li-sulfur batteries, Li-oxygen batteries, and nonhumidified fuel cells and as carbon precursors for electrode catalysts of fuel cells and electrode materials for batteries and supercapacitors. Due to their characteristic properties such as nonvolatility, high thermal stability, and high ionic conductivity, ILs appear to meet the rigorous demands/criteria of these various applications. However, for further development, specific applications for which these characteristic properties becom...

Application of Ionic Liquids to Energy Storage and Conversion Materials and Devices

It is of great interest to develop new carbon-based materials as electrodes for supercapacitors because the conventional electrodes of activated carbons in supercapacitors cannot meet the ever-increasing demands for high energy and power densities for electronic devices. Due to their high electronic conductivity and improved hydrophilic properties, together with their easy syntheses and functionalization, N-doped carbons have shown a great potential in energy storage and conversion applications. In this review, after a brief introduction of electrochemical capacitors, we summarize the advances, in the recent six years, in the preparation methods of N-doped carbons for applications in supercapacitors. We also discuss and predict futuristic research trends towards the design and syntheses of N-doped carbons with unique properties for electrochemical energy storage.

Review on recent advances in nitrogen-doped carbons: preparations and applications in supercapacitors

Sustainable technologies applied to energy-related applications should develop a pivotal role in the next decades. In particular, carbon dioxide capture from flue gases emitted by fossil-fueled power plants should play a pivotal role in controlling and reducing the greenhouse effect. Therefore, the development of new materials for carbon capture purposes has merged as central research line, for which many alternatives have been proposed. Ionic liquids (ILs) have emerged as one of the most promising choices for carbon capture, but in spite of their promising properties, some serious drawbacks have also appeared. Deep eutectic solvents (DESs) have recently been considered as alternatives to ILs that maintain most of their relevant properties, such as task-specific character, and at the same time avoid some of their problems, mainly from economic and environmental viewpoints. DES production from low-cost and natural sources, together with their almost null toxicity and total biodegradability, makes these sol...

Deep Eutectic Solvents: Physicochemical Properties and Gas Separation Applications

The inherent structure tunability, good affinity with CO2, and nonvolatility of ionic liquids (ILs) drive their exploration and exploitation in CO2 separation field, and has attracted remarkable interest from both industries and academia. The aim of this Review is to give a detailed overview on the recent advances on IL-based materials, including pure ILs, IL-based solvents, and IL-based membranes for CO2 capture and separation from the viewpoint of molecule to engineering. The effects of anions, cations and functional groups on CO2 solubility and selectivity of ILs, as well as the studies on degradability of ILs are reviewed, and the recent developments on functionalized ILs, IL-based solvents, and IL-based membranes are also discussed. CO2 separation mechanism with IL-based solvents and IL-based membranes are explained by combining molecular simulation and experimental characterization. Taking into consideration of the applications and industrialization, the recent achievements and developments on the t...

Ionic-Liquid-Based CO2 Capture Systems: Structure, Interaction and Process

A novel strategy for SO2 capture through multiple-site absorption in the anion of several azole-based ionic liquids is reported. An extremely high capacity of SO2 (>3.5 mol/mol) and excellent reversibility (28 recycles) were achieved by tuning the interaction between the basic anion and acidic SO2. Spectroscopic investigations and quantum-mechanical calculations showed that such high SO2 capacity originates from the multiple sites of interaction between the anion and SO2. These tunable azole-based ionic liquids with multiple sites offer significant improvements over commonly used absorbents, indicating the promise for industrial applications in acid gas separation.

Highly Efficient and Reversible SO2 Capture by Tunable Azole-Based Ionic Liquids through Multiple-Site Chemical Absorption

CO2 capture and storage (CCS) has attracted worldwide interest because CO2 makes a significant contribution to global warming and climate change as a major greenhouse gas. Ionic liquids are promising absorbents for carbon capture due to their negligible vapour pressures, wide liquid range, high thermal stabilities and tunable properties. This perspective review focuses on the recent advances in chemical absorption of CO2 using functionalized ionic liquids, including amino acid-based ionic liquids, azole-based ionic liquids, phenol-based ionic liquids, and so on. Strategies for how to enhance CO2 absorption capacity, reduce CO2 absorption enthalpy, and improve CO2 absorption kinetics are presented. The absorption mechanisms of these functionalized ionic liquids are explained at the molecular level through a combination of theoretical calculation and spectroscopic investigation. Particular attention is paid to the latest developments in carbon capture by non-amino anion-functionalized ionic liquids. In the last section, future directions and prospects for CO2 capture by functionalized ionic liquids are outlined.

The strategies for improving carbon dioxide chemisorption by functionalized ionic liquids

The search for a better carbon dioxide (CO2) capture material is attracting significant attention because of an increase in anthropogenic emissions. Porous materials are considered to be among the most promising candidates. A series of porous, nitrogen-doped carbons for CO2 capture have been developed by using high-yield carbonization reactions from task-specific ionic liquid (TSIL) precursors. Owing to strong interactions between the CO2 molecules and nitrogen-containing basic sites within the carbon framework, the porous nitrogen-doped compound derived from the carbonization of a TSIL at 500 degrees C, CN500, exhibits an exceptional CO2 absorption capacity of 193 mg of CO2 per g sorbent (4.39 mmol g(-1) at 0 degrees C and 1 bar), which demonstrates a significantly higher capacity than previously reported adsorbents. The application of TSILs as precursors for porous materials provides a new avenue for the development of improved materials for carbon capture.

Chongmin Wang

Papers

Highly Efficient and Reversible SO2 Capture by Tunable Azole-Based Ionic Liquids through Multiple-Site Chemical Absorption

The strategies for improving carbon dioxide chemisorption by functionalized ionic liquids

Efficient CO2 Capture by Porous, Nitrogen-Doped Carbonaceous Adsorbents Derived from Task-Specific Ionic Liquids