CO2 Batteries Research Articles

Recent advances in Zn–CO2 batteries for the co-production of electricity and carbonaceous fuels

Electrochemical CO 2 reduction has been considered a promising approach to neutralizing the global CO 2 level. As an intriguing technique, metal-CO 2 battery devices can not only capture CO 2 into valuable carbonaceous chemicals and reduce the CO 2 concentration in the atmosphere but enable energy conversion. Among metal-CO 2 batteries, aqueous Zn–CO 2 batteries, especially rechargeable systems, exhibit flexible CO 2 electrochemistry in terms of multi-carbon chemicals, which are gaseous or water-soluble, in favor of rechargeability and cycling durability of aqueous battery systems. Despite the increasing number of publications on Zn–CO 2 batteries in the past three years, this field is still in its beginning stage and facing many challenges considering the capability of CO 2 fixation and battery performance. Herein, we present a timely and overall summary of the recent progress in Zn–CO 2 batteries, including fundamental mechanisms, affecting factors on electrochemical performance, catalyst cathodes, and electrolytes (catholytes and anolytes). Besides, we assess the application potential of Zn–CO 2 batteries and compare this with those of alkali metal-CO 2 batteries based on CO 2 fixation and battery performance. Finally, we point out some current challenges for the further development of Zn–CO 2 batteries and put forward perspectives of the research directions for practical applications of Zn–CO 2 batteries in the future.

Highly Stable Single‐Atom Modified MXenes as Cathode‐Active Bifunctional Catalysts in Li–CO2 Battery

AbstractThe exploration of cathode catalysts with low overpotentials for the carbon dioxide reduction reaction (CRR) and carbon dioxide evolution reaction (CER) is essential for Li–CO2 batteries. MXenes have been suggested as potential candidates owing to their high electrical conductivity and effective CO2 activation performance. Herein, the stability and bifunctional CRR/CER catalytic activities of bare MXene (M2C), oxygen‐functionalized MXene (M2CO2), and single‐atom (SA) modified M2CO2 are systemically investigated. Among bare MXenes, Mo2C exhibits the best catalytic activity, comparable to that of carbon nanotubes, whereas oxygen‐functionalized MXene has poor activity. Notably, introducing an SA on the surface of oxygen‐functionalized MXene decreases the overpotential by 12.2%–68.1%, which can even outperform graphene catalysts, suggesting their potential as bifunctional cathode catalysts in Li–CO2 batteries. This high activity is appropriate reactivity in origin, as highlighted by the volcano‐type relationship between the Gibbs free energy and the overpotential for key steps. The descriptor ξ, which is related to adsorption behavior, is effective in determining bifunctional catalytic activity, which depends on the ability of SA electrons to fill antibonding orbitals and SA–oxygen/carbon bonding. This study not only identifies promising MXene‐based bifunctional CRR/CER catalysts but also provides a rational design rule for SA modified catalysts.

An environmentally friendly and low-cost catalyst for Li–CO2 batteries based on Co recovered from waste lithium-ion batteries

With the use of lithium batteries increasing year by year, resulting in a large number of waste lithium-ion batteries generated, bringing pressure to the ecological system while also causing a waste of Co resources. Although Co-based catalysts are also of interest in the Li–CO2 system, no research has been reported on the preparation of catalysts for value-added utilization of recovered Co. In this paper, Li–CO2 batteries with Co3O4/CNT cathodes were prepared by environmentally friendly hydrothermal method employing cobalt oxalate recycled from waste lithium-ion batteries as a Co source in combination with commercial CNT. Unlike traditional noble metal and transition metal-based catalysts, which are expensive and complicated, this work can further reduce the cost of batteries by recycling valuable Co sources from waste lithium-ion batteries. As a result, the battery has the discharge capacity of 2728 mAh g−1 at a current density of 100 mA g−1. Not only that, but it can reach more than 85 cycles at a limited capacity of 400 mAh g−1.

A High‐Energy Long‐Cycling Solid‐State Lithium‐Metal Battery Operating at High Temperatures

AbstractHigh‐energy rechargeable lithium‐ion batteries, especially solid‐state lithium metal batteries, are increasingly required to operate at elevated temperatures in addition to pursuing operation at low temperatures. However, the notorious chemical and electrochemical reactions at the interface between the Li‐anode and solid state electrolyte (SSE) make these batteries lose almost all of their capacity and power at elevated temperatures. Here, a safe and long‐cycle‐life solid‐state Li–CO2 battery operating at elevated temperatures by constructing a stable and high ionic conductive molten salts interface (MSI) is reported. The MSI can effectively improve the interface contact and suppress interface reactions and the thermal runaway between Li‐anode and Li1.5Al0.5Ge1.5P3O12 (LAGP)‐electrolyte even at high temperatures, thus enabling an ultra‐low interface impedance (≈15 Ω) and discharge/charge overpotential (≈15 mV) for high temperature symmetric battery. In addition, the MSI‐coated LAGP‐electrolyte shows an ultra‐flat and continuous surface that enables a homogeneous Li tripping/plating during cycles. As a result, the Li symmetric battery shows superior cycling stability over 600 h at 0.1 mA cm−2 at 150 °C. The assembled solid‐state Li–CO2 battery using Ru catalysts shows outstanding cycle stability over 980 cycles at 150 °C, with a capacity limitation of 500 mAhg–1 at 500 mA g−1.

Nanofibrous Cathode Catalysts with MoC Nanoparticles Embedded in N-Rich Carbon Shells for Low-Overpotential Li–CO2 Batteries

Li-CO2 batteries with high theoretical energy densities are recognized as next-generation energy storage devices for addressing the range anxiety and environmental issues encountered in the field of electric transportation. However, cathode catalysts with unsatisfactory activity toward CO2 absorption and reduction/evolution reactions hinder the development of Li-CO2 batteries with desired specific capacities and sufficient cycle numbers. In this work, a multifunctional nanofibrous cathode catalyst that integrates N-rich carbon shells embedded with molybdenum carbide nanoparticles and multiwalled carbon nanotube cores was designed and prepared. The N-rich carbon shell could strengthen the absorption capacity of CO2 and Li2CO3. The molybdenum carbide nanoparticles would improve the catalytic activity of both CO2 reduction and evolution reactions. The carbon nanotube cores would provide an efficient network for electron transportation. The synergistic effect of the cathode catalysts enhances the electrochemical performance of Li-CO2 batteries. A high cycling stability of more than 150 cycles at a current density of 250 mA g-1 with a cutoff capacity of 1000 mAh g-1 and a charge/discharge overpotential of less than 1.5 V is achieved. This work provides a feasible strategy for the design of a high-performance cathode catalyst for lithium-air batteries.

A Novel Energy Storage System Based on Carbon Dioxide Unique Thermodynamic Properties

Abstract This paper focuses on the thermodynamic performance and techno-economic assessment of a novel electrical energy storage technology using carbon dioxide as a working fluid. This technology, named CO2 battery and recently patented by Energy Dome SpA., addresses an energy market which has a great need for energy storage solutions able to handle the increasing share of nondispatchable renewable energy sources like photovoltaic and wind energy. After a brief introduction, the present study presents the concept of CO2 batteries and their operation. Then the detailed numerical model developed for the accurate calculation of system round trip efficiency is presented with the adopted assumptions and the optimization routine description. Results on the reference case and following sensitivity analysis confirm a round trip efficiency of around 77% (±2%) which makes CO2 batteries a very promising technology with respect to other energy storage systems based on thermodynamic cycles like compressed air and liquid air energy storage thanks to the high performance and the easiness of installation. Finally, calculation of system footprint, capital investment cost and levelized cost of storage are discussed.

“Water-in-Salt” and Nasicon Electrolyte-Based Na-CO2 Battery

Aprotic electrolytes are much less feasible for producing cost-effective Na metal-based CO2 batteries due to high cost and flammability. As an alternative electrolyte, super-concentrated electrolytes, referred to as “water-in-salt (WiS) electrolytes”, have been received attention due to their wide electrochemical stability window, cost-effectiveness, and non-flammability. However, the highly reactive Na metal prevents the direct use of WiS electrolytes because the unsolvated water molecules would react with the Na Metal.In this study, we demonstrated the ability of a WiS and NASICON electrolyte-based Na-CO2 battery for utilizing CO2 gas and serving as an energy storage cell. The NASICON separator allowed us to fabricate a hybrid Na-CO2 battery comprising Na metal as the anode material and WiS as the cathode electrolyte without damage of Na metal. Additionally, linear sweep voltammetry (LSV) with corresponding differential electrochemical mass spectroscopy (DEMS) measurements rendered the direct observation of H2 evolution retardation with increasing WiS concentration. Furthermore, we introduced a nano-sized Ru catalyst onto the current collector using Joule heating method for reducing the overpotential gap. Consequently, the Na-CO2 batteries with Ru@carbon current collector reduced the overpotential gap and exhibit a cycling endurance of over 75 cycles. Figure 1

Na@C composite anode for a stable Na|NZSP interface in solid-state Na–CO2 battery

Na–CO2 battery is one of the most promising energy storage devices for the exploration of Mar. To fix the evaporation problem of liquid electrolytes in an open system, solid-state electrolyte Na3Zr2Si2PO12 (NZSP) is used to fabricate a solid-state Na–CO2 battery. In the battery, the interface between the Na-metal anode and NZSP plays a vital role in improving electrochemical performance. The interfacial parasitic reaction between NZSP and Na-metal results in a Na-rich kinetically stable interphase. (200) and (−111) planes are the preferentially etched crystal planes of NZSP, as SiO4 and PO4 tetrahedrons on the planes are easily broken by extra Na-ion injection. Aside from the interfacial reaction, the poor contact between Na-metal and NZSP is a more serious problem, which leads to large interfacial resistance and poor cycling stability. To fix this problem, carbon black is mixed with melted Na-metal to prepare a composite anode (Na@C). The Na@C composite anode easily wets NZSP, thus decreasing the interfacial resistance from 918 to 98 Ω cm2. Symmetrical cells stably cycled 1100 h at 0.1 mA cm−2, when using Na@C as the electrode. Furthermore, Na–CO2 battery with Na@C composite anode also shows a prolonged cycling life.

Carbon Tube-Based Cathode for Li-CO2 Batteries: A Review.

Metal–air batteries are considered the research, development, and application direction of electrochemical devices in the future because of their high theoretical energy density. Among them, lithium–carbon dioxide (Li–CO2) batteries can capture, fix, and transform the greenhouse gas carbon dioxide while storing energy efficiently, which is an effective technique to achieve “carbon neutrality”. However, the current research on this battery system is still in the initial stage, the selection of key materials such as electrodes and electrolytes still need to be optimized, and the actual reaction path needs to be studied. Carbon tube-based composites have been widely used in this energy storage system due to their excellent electrical conductivity and ability to construct unique spatial structures containing various catalyst loads. In this review, the basic principle of Li–CO2 batteries and the research progress of carbon tube-based composite cathode materials were introduced, the preparation and evaluation strategies together with the existing problems were described, and the future development direction of carbon tube-based materials in Li–CO2 batteries was proposed.

Highly safe and stable Li–CO2 batteries using conducting ceramic solid electrolyte and MWCNT composite cathode

This study demonstrates a Li–CO2 battery with lithium aluminum titanium phosphate (LATP) solid electrolyte and carbon cloth-based multi-walled carbon nanotubes (MWCNTs) cathode. The LATP powder is synthesized by a facile solution-based method. The structural properties of as-prepared LATP are evaluated using X-ray diffraction (XRD) and Rietveld refinement analysis. The ionic conductivity of the LATP pellet is measured by electrochemical impedance spectroscopy (EIS) and found to be ∼5.43 × 10−4 S cm−1. Further, the morphology of the carbon cathodes with MWCNTs is examined by scanning electron microscopy (SEM). The electrochemical performance is evaluated by galvanostatic tests at a current density of 60 mA g−1 with a cut-off capacity of 600 mAh g−1 for 50 cycles. The test results signify the high performance and good cyclic stability. The Li–CO2 cell has delivered a maximum capacity of 5255 mAh g−1. Finally, to investigate further, post mortem analysis is carried out in which the discharge products are thoroughly characterized by Raman spectroscopy and X-ray photoelectron spectroscopy (XPS). This work also introduces a new geometry for Li–CO2 batteries with LATP as the solid electrolyte, enabling the development of all-solid-state batteries.

In-situ construction of Cu–Co4N@CC hierarchical binder-free cathode for advanced and flexible Li–CO2 batteries: Electron structure and mass transfer modulation

Li–CO2 batteries with high energy density presents great promising to meet carbon neutrality. Herein, a binder-free cathode is obtained by in-situ growth of ZIF-67-derived Co4N with Cu integration on carbon cloth (CC), which is developed as the advanced catalytic cathode for Li–CO2 batteries. After optimizing the components, the derived Li–CO2 batteries can present a discharge capacity beyond 31 000 mA h g−1 at a current density of 100 mA g−1 as well as an excellent long-term stable cycle life up to 131 cycles at 200 mA g−1. Benefitting from the reorganization of the electronic structure on the Co4N active surface by the introduction of Cu, the reduction of CO2 and the decomposition of discharge products tend to be smoothly, and the assembled batteries exhibit a low overpotential of 1.32 V (Li/Li+) at 100 mA g−1. The superior catalytic performances of Cu–Co4N@CC cathode are well-demonstrated by the combination of experiments and theoretical calculations. Moreover, this binder-free cathode with flexible feature has been proven to be suitable for the development of wearable electronic devices by the assembled flexible Li–CO2 batteries. These findings shed a new light on the expansion of excellent cathode based on non-noble bimetal for advanced and wearable Li–CO2 batteries.

Rational Design of Nanostructured Metal/C Interface in 3D Self‐Supporting Cellulose Carbon Aerogel Facilitating High‐Performance Li‐CO2 Batteries

AbstractThe sluggish kinetics of CO2 reduction and evolution reaction (CRR and CER) on the Li–CO2 battery cathode seriously hindered its practical application. Rational design of the Ru/C interface is expected to simultaneously decrease the free energy barrier of intermediate species and create a favorable electronic structure, effectively promoting the catalytic reaction kinetics of the CRR and CER. Herein, a 3D self‐supporting cellulose carbon aerogel (CCA) with well‐defined Ru/C interfaces (Ru@CCA) is synthesized as an advanced CO2‐breathing cathode for Li–CO2 batteries. The results show that the energy efficiency significantly improves to 80% with a high discharge capacity of 10.71 mA h cm−2 at 20 µA cm−2, and excellent cyclic stability of 421 cycles at 100 µA cm−2. These outstanding performances are highly competitive compared with state‐of‐art Li–CO2 cathodes. In addition, the unique interface design strategy is applied to other non‐noble metal@CCA cathodes, which confirms the advantages of constructing nanostructure metal/C interfaces for improving the kinetics of CRR and CER. This fundamental understanding of the structure–performance relationship provides new inspiration for designing highly efficient cathode catalysts for Li–CO2 batteries.

Covalent Organic Framework for Rechargeable Batteries: Mechanisms and Properties of Ionic Conduction

AbstractIonic conduction plays a critical role in the process of electrode reactions and the charge transfer kinetics in a rechargeable battery. Covalent organic frameworks (COFs) have emerged as an exciting new class of ionic conductors, and have made great progress in terms of their application in rechargeable batteries. The unique features of COFs, such as well‐defined directional channels, functional diversity, and structural robustness, endow COF‐based conductors with a low ionic diffusion energy barrier and excellent temperature tolerance, which are much superior to the classic inorganic or polymer conductors. Here, a comprehensive analysis and summary of the unique ion‐conducting behavior of COF‐based conductors are presented, and the design principles for ion‐conducting COFs are emphasized. Moreover, a systematic overview of the recent progress in the development of ion‐conducting COFs serving as electrodes, separators, solid electrolytes, and artificial interphase materials for diverse battery applications, such as metal‐ion batteries, lithium metal batteries, lithium–sulfur batteries, lithium–CO2batteries, zinc–air batteries, etc., is proposed. This review is expected to provide theoretical guidance for design of novel kinds of ionic conductor bearing intrinsic framework structures and to boost further research enthusiasm for ion‐conducting COFs in rechargeable batteries.

Boosting Cycling Stability and Rate Capability of Li–CO2Batteries via Synergistic Photoelectric Effect and Plasmonic Interaction

AbstractSluggish CO2reduction/evolution kinetics at cathodes seriously impede the realistic applications of Li–CO2batteries. Herein, synergistic photoelectric effect and plasmonic interaction are introduced to accelerate CO2reduction/evolution reactions by designing a silver nanoparticle‐decorated titanium dioxide nanotube array cathode. The incident light excites energetic photoelectrons/holes in titanium dioxide to overcome reaction barriers, and induces the intensified electric field around silver nanoparticles to enable effective separation/transfer of photogenerated carriers and a thermodynamically favorable reaction pathway. The resulting Li–CO2battery demonstrates ultra‐low charge voltage of 2.86 V at 0.10 mA cm−2, good cycling stability with 86.9 % round‐trip efficiency after 100 cycles, and high rate capability at 2.0 mA cm−2. This work offers guidance on rational cathode design for advanced Li–CO2batteries and beyond.

Boosting Cycling Stability and Rate Capability of Li-CO2 Batteries via Synergistic Photoelectric Effect and Plasmonic Interaction.

Sluggish CO2 reduction/evolution kinetics at cathodes seriously impede the realistic applications of Li-CO2 batteries. Herein, synergistic photoelectric effect and plasmonic interaction are introduced to accelerate CO2 reduction/evolution reactions by designing a silver nanoparticle-decorated titanium dioxide nanotube array cathode. The incident light excites energetic photoelectrons/holes in titanium dioxide to overcome reaction barriers, and induces the intensified electric field around silver nanoparticles to enable effective separation/transfer of photogenerated carriers and a thermodynamically favorable reaction pathway. The resulting Li-CO2 battery demonstrates ultra-low charge voltage of 2.86 V at 0.10 mA cm-2 , good cycling stability with 86.9 % round-trip efficiency after 100 cycles, and high rate capability at 2.0 mA cm-2 . This work offers guidance on rational cathode design for advanced Li-CO2 batteries and beyond.

A Moisture‐Assisted Rechargeable Mg−CO2 Battery

AbstractNew sustainable energy conversion and storage technologies are required to address the energy crisis and CO2 emission. Among various metal–CO2 batteries that utilize CO2 and offer high energy density, rechargeable Mg−CO2 batteries based on earth‐abundant and safe magnesium (Mg) metal have been limited due to the lack of a compatible electrolyte, operation atmosphere, and unambiguous reaction process. Herein, the first rechargeable nonaqueous Mg−CO2 batteries have been proposed with moisture assistance in a CO2 atmosphere. These display more than 250 h cycle life and maintain the discharge voltage over 1 V at 200 mA g−1. Combining with the experimental observations and theoretical calculations, the reaction in the moisture‐assisted Mg−CO2 battery is revealed to be 2 Mg+3 CO2+6 H2O↔2 MgCO3⋅3 H2O+C. It is anticipated that the moisture‐assisted rechargeable Mg−CO2 batteries would stimulate the development of multivalent metal‐CO2 batteries and extend CO2 fixation and utilization for carbon neutrality.

Electronic State Modulation and Reaction Pathway Regulation on Necklace‐Like MnOx‐CeO2@Polypyrrole Hierarchical Cathode for Advanced and Flexible Li–CO2 Batteries

AbstractLi–CO2 batteries provide the possibility for synchronous implementation of carbon neutrality and development of advanced energy storage devices. Catalytic cathodes composed of well‐designed conductive substrates and active materials are critical to the improvement of Li–CO2 batteries. Herein, MnOx‐CeO2 hollow nanospheres are strung together by conductive polypyrrole (PPy) via post‐in‐situ polymerization, and a necklace‐like MnOx‐CeO2@PPy hierarchical cathode with excellent flexibility and self‐supporting feature is constructed. Benefitting from the excellent conductivity of PPy, the binder‐free structure, and the greatly exposed catalytic active sites, the MnOx‐CeO2@PPy based Li–CO2 batteries exhibit superior discharge capacity (13631 mA h g–1 at 100 mA g–1) and cycle performance (253 cycles) as well as a low overpotential of 1.49 V. Of particular note, the flexible freestanding film is confirmed as a potential catalytic cathode for flexible Li–CO2 batteries. The density functional theory calculations, combined with experimental tests, are performed to gain insights into the enhanced substrate adsorption capacity, the optimized electronic structure of the active surface MnOx‐CeO2 (111), the concentrated electrons on the reaction sites Ce, and the electrochemical mechanism. This work initiates the use of conductive polymers for catalytic cathodes in Li–CO2 batteries, which provide new opportunities for promoting the performance of various energy storage devices.

Highly dispersed Bi clusters for efficient rechargeable Zn−CO2 batteries

Zn−CO2 batteries hold great promise for carbon-neutral and electricity generation simultaneously, whereas the main obstacle is the development of electrocatalysts with high activity and durability towards CO2 reduction reaction (CRR). Herein, we design atomically dispersed Bi clusters supported on hollow carbon spheres (BiC/HCS) for effectively reducing CO2 to formate, which shows the highest faradaic efficiency of 97 ± 2% at − 0.6 V vs RHE, being comparable to the previously best reported values of Bi-based materials. Experimental and theoretical analyses reveal that the atomic-level Bix clusters not only enable high CO2 adsorption but also stabilize the key *HCOO intermediate with a low free energy barrier. Further, an assembled rechargeable Zn−CO2 battery with BiC/HCS as the cathode achieves a peak power density of 7.2 ± 0.5 mW cm−2 as well as an impressive rechargeability of 200 cycles. This work provides a promising alternative for CO2 utilization and energy storage by Zn−CO2 batteries.Graphical AbstractBi clusters anchored on hollow carbon spheres have developed as an excellent cathode for Zn−CO2 battery. The catalyst presents a maximal formate faradaic efficiency of 97 ± 2% at − 0.6 V vs RHE as well as good durability. The assembled Zn−CO2 battery achieves a peak power density of 7.2 ± 0.5 mW cm−2 and energy efficiency of 68.9% (@ 3 mA cm−2), and a more than 200 cycle rechargeability. [Display omitted]

Functional Aqueous Zinc–Acetylene Batteries for Electricity Generation and Electrochemical Acetylene Reduction to Ethylene

AbstractThe available processes for removing acetylene impurities from crude ethylene are tremendously energy‐intensive. Herein, we demonstrate a novel aqueous Zn–C2H2 battery, which not only switches energy‐consuming acetylene removal to electricity generation, but also reduces acetylene to ethylene through a unique discharge mechanism: C2H2+Zn+H2O→C2H4+ZnO. Under a pure acetylene stream, this Zn–C2H2 battery exhibits an open circuit potential of 1.14 V and a peak power density of 2.2 mW cm−2, which exceed those of reported Zn–CO2 batteries. Even for simulated crude ethylene, the Zn–C2H2 battery manifests an acetylene conversion of 99.97 % and continuously produces polymer‐grade ethylene with only ≈3 ppm acetylene during a long‐term discharge operation. Such a functional battery is universally appliable for reducing other alkynes and generating electricity. Therefore, this work provides an effective strategy for green ethylene purification and the design of functional batteries.

Tuning the Metal Electronic Structure of Anchored Cobalt Phthalocyanine via Dual‐Regulator for Efficient CO2 Electroreduction and Zn–CO2 Batteries

AbstractHeterogeneous macromolecule catalysts have been known as efficient electrocatalysts for CO2 reduction reaction, however, manipulating the activity of heterogeneous molecules via controllable metal electronic structure is still challenging. Herein, different CO2 activated 3D, robust, nitrogen‐doped hollow carbon spheres are synthesized to anchor cobalt phthalocyanine as molecularly dispersed electrocatalysts, where the electron‐withdrawing coeffect of carbon defects and heteroatom N is responsible for tuning the electronic structure of metal center. The optimal electrocatalyst reveals high CO faradaic efficiency (FECO) of 95.68%, turnover frequency of 13.80 s−1, and current density of 16.49 mA cm−2 at an overpotential of 760 mV. The control experiment and DFT calculations unveil that the significant activity is mainly ascribed to the optimal electron‐withdrawing coeffect of carbon defects and pyrrolic N, which reduce the electron density of Co center to facilitate CO2 activated to form *COOH intermediate on Co(I) active sites during electrocatalysis. The 2p‐charge loss of Co is summarized as an activity descriptor, which steers the current density and production rate toward CO. Furthermore, the design strategy can universally fabricate the hybrid MPc catalyst with transitional metal (Ni, Fe) site while a rechargeable Zn–CO2 battery is devised to deliver a maximal power density of 1.02 mW cm−2.