Rechargeable Li-CO2 Batteries Research Articles

Cationic metal-organic framework derived ruthenium-copper nano-alloys in porous carbon to catalytically boost the cycle life of Li-CO2 batteries.

Rechargeable Li-CO2 batteries are an innovative energy storage technology with broad application prospects owing to their superb energy density and ability to capture the greenhouse gas CO2. However, they are still suffering from severe challenges in the formation and decomposition of electrochemically sluggish Li2CO3 discharge products, resulting in poor battery performance. Development of an efficient cathodic electrocatalyst has the potential to address these issues by catalytically boosting the conversion of Li2CO3. Herein, we have designed a Ru-Cu nanoalloy decorated porous carbon (Ru-Cu@NPC) material derived from an anion-exchanged cationic MOF, and it can serve as an efficient cathode electrocatalyst for Li-CO2 batteries. Benefitting from the uniform distribution of ultrafine Ru-Cu nanoalloys with high catalytic performance, Ru-Cu@NPC displays excellent CO2 reduction and evolution activities. Impressively, the Li-CO2 battery with the Ru-Cu@NPC catalyst exhibits a remarkably low potential gap of 0.93 V at 100 mA g-1 and a stable discharge/charge cycling performance of more than 400 cycles at a high current density of 400 mA g-1 within a limiting capacity of 1000 mA h g-1. The study provides an opportunity for the research of cationic MOF derived bimetallic catalysts in the Li-CO2 battery field.

Correction: A rechargeable Li–CO2 battery based on the preservation of dimethyl sulfoxide

Correction for ‘A rechargeable Li–CO2 battery based on the preservation of dimethyl sulfoxide’ by Zhenhua Lu et al., J. Mater. Chem. A, 2022, 10, 13821–13828, https://doi.org/10.1039/d2ta02586h.

Incorporated O-CoP nanosheets with an O–P interpenetrated interface as electrocatalytic cathodes for rechargeable Li–CO2batteries

An electrocatalytic material based on oxygen-decorated CoP nanosheets with an O–P interpenetrated interface was prepared for rechargeable Li–CO2battery cathodes.

Super-assembled atomic Ir catalysts on Te substrates with synergistic catalytic capability for Li-CO2 batteries

Rechargeable Li-CO2 batteries (LCBs) are considered as a promising candidate for the next generation energy storage system, but still be impeded by the lack of high-performance cathode catalyst and poor understanding for the complicated reaction mechanism. In the present work, we demonstrate that the catalytic capability of cathode catalyst of LCBs can be remarkably enhanced from the accelerated reaction kinetics using a p-type substrate as adsorption/desorption promoter for refined reaction route. A carbon-free atomic Ir-Te cathode catalyst with Ir atomic cluster is uniformly super-assembled on the surface of Te nanowires forming an amorphous surface layer (ca. 3 nm) to maximize the catalytic capability of active Ir sites and provide a refined reaction pathway due to synergistic effect of Ir active sites and Te substrate. The adsorption ability of Li2C2O4 during discharging and the desorption ability of CO2 species during charging of the p-type Te substrate could both promote the catalytic reaction kinetics and optimize the reaction pathways on Ir active sites. Finally, a large specific capacity of 13,247.1 mAh g−1 and an excellent high rate cyclability with stably over 350 and 200 cycles at the current density of 1000 and 2000 mA g−1 are achieved. This contribution provides a rational design strategy for high performance cathode catalyst, and intrinsic insight towards the understanding the reaction mechanisms of LCBs.

Single-metal site-embedded conjugated macrocyclic hybrid catalysts enable boosted CO2 reduction and evolution kinetics in Li-CO2 batteries

Rechargeable Li-CO2 batteries, an emerging battery technology to confront the environmental and energy crises, hold promise for CO2 fixation and energy storage. However, state-of-the-art Li-CO2 systems generally suffer from sluggish CO2 reduction/evolution reaction kinetics, and powerful catalysts that can simultaneously facilitate both processes are much desired but largely unrealized. Here, we report a series of Ru, metal-chelated conjugated N4-macrocyclic metal complex (M-CPY) and carbon nanotube (CNT)-based hybrid materials (Ru/[email protected]) with the advantages of highly dispersed Ru and M-CPY, high-conductivity, and tunable loadings that can be applied as multi-functional cathode catalysts. Ru/[email protected] cells deliver an ultra-low overpotential (0.84 V) and enable fully reversible discharge/charge with a high specific capacity of 24,740 mAh/g within 2.0–4.5 V at 200 mA/g. It can rapidly discharge/charge for 180 cycles at 500 mA/g, and the CO2 activation process is intensively investigated by density functional theory (DFT) calculations.

Ultrafine Co-Doped NiO Nanoparticles Decorated on Carbon Nanotubes Improving the Electrochemical Performance and Cycling Stability of Li–CO2 Batteries

Rechargeable Li–CO2 batteries offer a sustainable strategy for CO2 utilization and energy storage in an environmentally friendly way. However, the current Li–CO2 batteries are restrained by unsatisfactory electrochemical performance and lack of cost-effectiveness in practical application. Thus, developing low-cost and highly effective electrode materials is crucial. Inspired by the concept of high nickel and low cobalt content in the electrode material, ultrafine Co0.1Ni0.9Ox nanoparticles decorated on carbon nanotubes (Co0.1Ni0.9Ox/CNT) are first developed in this work. Through various characterization techniques, the effects of doping Co2+ cations on the properties and electrochemical performance are systematically studied. At a current density of 100 mA g–1, a battery with the Co0.1Ni0.9Ox/CNT electrode delivers a high capacity of 5871.41 mA h g–1 with a Coulombic efficiency of 92.91% and a low overpotential of 3.94 V with an energy efficiency of 68%. At a cutoff capacity of 500 mA h g–1, the battery based on the Co0.1Ni0.9Ox/CNT electrode can be easily operated for 50 cycles without the trace of capacity degradation, which is nearly twice more than those with the NiO/CNT and CNT electrodes. Compared with the NiO/CNT electrode, the Co0.1Ni0.9Ox/CNT electrode exhibits superior electrocatalytic activity in oxidation and evolution reactions of CO2, which results from doping Co2+ cations in the NiO lattice to improve the p-type electronic conductivity. In addition, the polymer-like discharge products affected by doping Co2+ provide better reaction interfaces, curtailing the overpotential and reducing the life span. The results enlighten new ideas of fabricating high-performance and cost-effective electrode materials for prolonging the cycling life of Li–CO2 batteries toward practical applications.

Redox Mediator-Enhanced Performance and Generation of Singlet Oxygen in Li-CO2 Batteries.

Rechargeable Li-CO2 batteries as a novel system developed in recent years directly use CO2 as the reactant, which enables deeper penetration of energy storage and CO2 utilization. The Li-CO2 battery system, however, is at an early stage, and many challenges remained to be overcome urgently, especially the problem of high over-potential during the charging process. Here, we report a redox mediator, phenoxathiin, to assist the decomposition of Li2CO3 during the charging process, which effectively reduces the over-potential and improves the cycling performance of the battery. Furthermore, we detect the presence of singlet oxygen during the oxidation of Li2CO3 by phenoxathiin, which reveals more of the underlying science of the reaction mechanism of the Li-CO2 battery.

Protecting Li-metal anode with ethylenediamine-based layer and in-situ formed gel polymer electrolyte to construct the high-performance Li–CO2 battery

Rechargeable Li–CO2 batteries have attracted extensive attentions since their excellent abilities of absorbing CO2 and delivering super-high energy density. Recently, many effective catalysts have been developed to improve the performance of Li–CO2 batteries, which nevertheless is still inhibited by problems derived from Li anodes and liquid electrolyte, such as Li dendrites and electrolyte leakage. In this work, we construct Li-ethylenediamine (LE) layer on Li (LE-Li) and use it to further react with tetraglyme in battery to obtain tetraglyme-based polymer electrolyte (TPE). The uniform LE layer coupled with in-situ formed TPE can not only restrain dendrite generation, Li-induced side reaction and corresponding passivation/pulverization, but also reduce interfacial impedance and enable battery work normally at bending condition. Therefore, the LE-Li electrode presents the more stable electrochemical property than the pure Li anode in symmetric battery. Additionally, the Li–CO2 battery using LE-Li/TPE displays high discharge capacity of 22873 mAh g−1 and good rate capability under full discharge/charge condition. When operated at cut-off capacity, this cell can steadily run for 104 cycles with a small overpotential of <1.9 V, which is better than bare Li/liquid electrolyte-based Li–CO2 battery. The LE-Li/TPE based Li–CO2 flexible cell also shows superior performance even at different bending angles.

A Renewable Light-Promoted Flexible Li-CO2 Battery with Ultrahigh Energy Efficiency of 97.9.

Directly converting and storing abundant solar energy in next-generation energy storage devices is of central importance to build a sustainable society. Herein, a new prototype of a light-promoted rechargeable and flexible Li-CO2 battery with a TiO2 /carbon cloth (CC) cathode is reported for the direct utilization of solar energy to promote the kinetics of the carbon dioxide reduction reaction and carbon dioxide evolution reaction (CO2 ER). Under illumination, photoelectrons are generated in the conduction band of TiO2 /CC, followed by the enhancing diffusion of electrons and lithium ions during the discharge process. The photoelectrons on the cathode surface can regulate the morphology of the discharge product Li2 CO3 , contributing to boosting the kinetics of the subsequent CO2 ER process. In the reverse charge process, photogenerated holes can favor the decomposition of Li2 CO3 , leading to a negative charge potential of 2.88V without increased polarization over ≈60h of cycling. Owing to an ultralow overpotential of 0.06V between the discharge and charge process, an ultrahigh energy efficiency of 97.9% is attained under illumination. The introduction of a light-promoted flexible Li-CO2 battery can pave the way toward developing the use of solar energy to address the charging overpotential of conventional Li-CO2 batteries.

Rechargeable LiCO2 Batteries with Graphdiyne as Efficient Metal‐Free Cathode Catalysts

AbstractA rechargeable LiCO2 battery is one of the promising power sources for utilizing the greenhouse gas CO2 in a sustainable approach. However, highly efficient catalysts for reversible formation/decomposition of insulating discharge product, Li2CO3, are the main challenge, which can boost the cycle stability. Herein, 2D single‐atom‐thick graphdiyne (GDY) with abundant acetylenic bond sites is prepared by a bottom‐up cross‐coupling reaction strategy and used as metal‐free catalysts for reversible LiCO2 batteries. The prepared GDY has a rich diacetylenic unit and atomic‐level in‐plane pores in the network, which can chemically adsorb the CO2 molecules and easily promote the Li+ diffusion and thereby resulting in uniform nucleation and reversible formation/decomposition of the discharge product. The GDY hybrid cathodes show a small overpotential gap of 1.4 V at a current density of 50 mA · g−1, a high full discharge capacity of 18 416 mAh · g−1 at 100 mA · g−1, and outstanding long‐term stability of 158 cycles at 400 mA · g−1 with a curtailing capacity of 1000 mAh · g−1. Furthermore, a flexible belt‐shaped LiCO2 battery is fabricated as a proof of concept with a high gravimetric energy density of 165.5 Wh · kg−1 (based on the mass of the whole device) as well as excellent mechanical flexibility.

Research status and perspectives of rechargeable Li-CO2 battery

As a new energy storage conversion device, rechargeable Li-CO2 batteries have attracted more and more attention because the charge and discharge of the battery can be realized by the reversible conversion of CO2. In this paper, the development of Li-CO2 battery is briefly introduced, and the reversible reaction mechanism of Li-CO2 battery is reviewed in real time. Meanwhile, the current research work on lithium anode, electrolyte, cathode catalyst, and other key components of Li-CO2 battery is overall reviewed, and the main problems and challenges still facing are further discussed and elaborated. Then, based on the detailed classification and deeply understand of the current research works, we summarized the role of battery components in improving battery performance. Finally, the future development directions and the design idea of high-performance Li-CO2 battery are prospected.

Exfoliation of covalent organic frameworks into MnO2-loaded ultrathin nanosheets as efficient cathode catalysts for Li-CO2 batteries

Rechargeable Li-CO2 batteries have been studied extensively as an attractive strategy for simultaneous energy storage and CO2 fixation to address the global environmental and energy crisis. However, state-of-the-art Li-CO2 systems still suffer from unsatisfactory performance. Here, we successfully exfoliated quinone-based covalent organic frameworks (COFs) into large-scale and ultrathin MnO2/2,6-diaminoanthraquinone-2,4,6-triformylphloroglucinol (DQTP)-COF-nanosheet (NS) hybrid materials. The obtained ultrathin nanosheets (as thin as 1.87 nm) synergistically integrate quinone-COF-NSs with MnO2 and serve as powerful cathode catalysts in Li-CO2 batteries. MnO2/DQTP-COF-NS-3 has a high discharge capacity of 42,802 mAh/g at 200 mA/g. Additionally, it is durable for higher-stress test with a negligible change of overpotential from 500 to 1,000 mA/g and is discharged/charged rapidly for 120 cycles at 1 A/g. Moreover, the CO2 activation mechanism is discussed and supported by density functional theory (DFT) calculations. This work may pave a new way for exploring porous crystalline materials as efficient cathode catalysts for Li-CO2 batteries.

Photoinduced homogeneous RuO2 nanoparticles on TiO2 nanowire arrays: A high-performance cathode toward flexible Li–CO2 batteries

Rechargeable Li–CO2 battery as a CO2 utilization and conversion device has attracted worldwide attention in recent years due to its high energy density and environmental friendliness. However, its practical utilization is primarily hindered by unsatisfactory electrochemical performances (such as high over-potential, low capacity, and poor cycle life), mainly caused by the insulating/insoluble discharge product, Li2CO3. Herein, a free-standing cathode of RuO2 nanoparticles decorated on TiO2 nanowire arrays based on flexible carbon textiles (RuO2–TiO2 NAs/CT) is synthesized by combining hydrothermal strategy with photodeposition technique. The flexible cathode can be directly used in Li–CO2 battery and exhibit excellent electrochemical performances with lower over-potential for charge/discharge process, higher discharge capacity, and especially, longer cycle life up to 1904 h (238 cycles). Additionally, a flexible battery is also assembled based on the obtained flexible cathode. Meanwhile, we revealed that the polarization of Li–CO2 battery can be regulated with the assistance of illumination.

Understanding the Dual-Phase Synergy Mechanism in Mn2O3-Mn3O4 Catalyst for Efficient Li-CO2 Batteries.

Rechargeable Li-CO2 batteries have been receiving intense interest because of their high theoretical energy density and environmentally friendly CO2 fixation ability. However, due to the sluggish CO2 reduction/evolution reaction (CRR/CER) kinetics, the current Li-CO2 batteries still suffer from severe polarization and poor cycling stability. Herein, we designed and in situ synthesized sea urchinlike Mn2O3-Mn3O4 nanocomposite and explored the synergistic effect between Mn2O3 and Mn3O4 during charge-discharge process in Li-CO2 batteries. It is found that Mn3O4 can effectively promote the kinetics of CRR process, and Mn2O3 can induce the nucleation of Li2CO3 and promote its decomposition (CER). Benefiting from the dual-phase synergy, the Mn2O3-Mn3O4 cathode combines the respective catalytic advantages of the both and delivers a high full discharge capacity of 19 024 mAh g-1, a low potential gap of 1.24 V, and durable cycling stability (1380 h) at a current density of 100 mA g-1. Moreover, based on experimental results and density functional theory (DFT) calculations, a charge-discharge process model of the Mn2O3-Mn3O4 cathode was established to display the electrochemical reaction mechanism. We hope that this design strategy can encourage further studies for efficient cathode catalysts to accelerate the practical application of Li-CO2 batteries and even the metal-air batteries.

Understanding Reaction Pathways in High Dielectric Electrolytes Using β-Mo2C as a Catalyst for Li-CO2 Batteries.

The rechargeable Li-CO2 battery has attracted considerable attention in recent years because of its carbon dioxide (CO2) utilization and because it represents a practical Li-air battery. As with other battery systems such as the Li-ion, Li-O2, and Li-S battery systems, understanding the reaction pathway is the first step to achieving high battery performance because the performance is strongly affected by reaction intermediates. Despite intensive efforts in this area, the effect of material parameters (e.g., the electrolyte, the cathode, and the catalyst) on the reaction pathway in Li-CO2 batteries is not yet fully understood. Here, we show for the first time that the discharge reaction pathway of a Li-CO2 battery composed of graphene nanoplatelets/beta phase of molybdenum carbide (GNPs/β-Mo2C) is strongly influenced by the dielectric constant of its electrolyte. Calculations using the continuum solvents model show that the energy of adsorption of oxalate (C2O42-) onto Mo2C under the low-dielectric electrolyte tetraethylene glycol dimethyl ether is lower than that under the high-dielectric electrolyte N,N-dimethylacetamide (DMA), indicating that the electrolyte plays a critical role in determining the reaction pathway. The experimental results show that under the high-dielectric DMA electrolyte, the formation of lithium carbonate (Li2CO3) as a discharge product is favorable because of the instability of the oxalate species, confirming that the dielectric properties of the electrolyte play an important role in the formation of the discharge product. The resulting Li-CO2 battery exhibits improved battery performance, including a reduced overpotential and a remarkable discharge capacity as high as 14,000 mA h g-1 because of its lower internal resistance. We believe that this work provides insights for the design of Li-CO2 batteries with enhanced performance for practical Li-air battery applications.

Boron-doped carbon microspheres as a new catalyst for rechargeable Li-CO2 batteries

Li-CO2 batteries are thought to be a promising technology for it can combine storing energy with mitigating the “greenhouse effect.” However, CO2 electrochemical reduction reaction is known to be a kinetically sluggish one. Therefore, researchers are committed to exploring catalysts with high catalytic activity to drive the reaction. In this study, boron-doped carbon microspheres (B-CMs) with mesoporous structure and large specific surface area were prepared using one-step impregnation followed by calcination. Active sites are increased by the positively charged boron atoms in B-CMs, thus, endowing higher catalytic performance for Li-CO2 batteries. The Li-CO2 battery with B-CMs cathode exhibited excellent performance, delivering a high discharge capacity of 17,429 and 11,975 at the current density of 200 and 500 respectively, and can stably run 90 cycles at the current density of 200 with a limited capacity of 1000

High-Performance, Long-Life, Rechargeable Li-CO2 Batteries based on a 3D Holey Graphene Cathode Implanted with Single Iron Atoms.

A highly efficient cathode catalyst for rechargeable Li-CO2 batteries is successfully synthesized by implanting single iron atoms into 3D porous carbon architectures, consisting of interconnected N,S-codoped holey graphene (HG) sheets. The unique porous 3D hierarchical architecture of the catalyst with a large surface area and sufficient space within the interconnected HG framework can not only facilitate electron transport and CO2 /Li+ diffusion, but also allow for a high uptake of Li2 CO3 to ensure a high capacity. Consequently, the resultant rechargeable Li-CO2 batteries exhibit a low potential gap of ≈1.17 V at 100 mA g-1 and can be repeatedly charged and discharged for over 200 cycles with a cut-off capacity of 1000 mAh g-1 at a high current density of 1 A g-1 . Density functional theory calculations are performed and the observed appealing catalytic performance is correlated with the hierarchical structure of the carbon catalyst. This work provides an effective approach to the development of highly efficient cathode catalysts for metal-CO2 batteries and beyond.

Achieving Low Charge Overpotential in a Li-CO2 Battery with Bimetallic RuCo Nanoalloy Decorated Carbon Nanofiber Cathodes

The rechargeable aprotic Li-CO2 batteries are novel and innovative technology for promising energy storage devices owing to the superb energy density and capability of directly utilizing the greenhouse gases CO2. However, they are still suffering from a severe challenge in decomposing the Li2CO3 discharge products, leading to poor batteries performance. Here we for the first time design and completely synthesize alloyed RuCo nanoparticles evenly dispersed on carbon nanofibers (RuCo/CNFs) as highly active electrocatalysts for Li-CO2 batteries. In particular, Li-CO2 battery with the optimal bimetallic Ru82Co18/CNFs cathode electrocatalyst demonstrates a remarkably reduced charge voltage of 3.75 V and maintains a stable cycling performance of over 90 cycles. An unexpected discharge capacity as high as 17 270 mAh g–1 with a superb Coulombic efficiency of 98.9% is also obtained at 300 mA g–1. Moreover, such a Li-CO2 battery shows outstanding rate capability even at a large current density of 2000 mA g–1. The p...

An ultra-long life, high-performance, flexible Li–CO2 battery based on multifunctional carbon electrocatalysts

Integrating CO2 utilization and renewable energy delivery/storage, the rechargeable Li–CO2 battery has been considered as a promising candidate for next-generation secondary batteries. However, high-performance catalyst(s) for efficient formation and decomposition of the discharge product, Li2CO3, are an imperative part of a Li–CO2 battery. The development of flexible Li–CO2 batteries extends their applications into compliant and wearable devices/systems, but at the same time imposes a big challenge for battery fabrication and lifetime enhancement. In this study, a rechargeable quasi-solidus flexible Li–CO2 battery was designed and fabricated using highly active N,S-doped carbon nanotubes (N,S-doped CNTs) as the cathode catalyst, and a smart polymer gel as the flexible electrolyte. This newly-developed flexible Li–CO2 battery exhibited a capacity as high as 23560 mAh g−1 based on the catalyst mass and an ultra-long lifetime of up to 538 cycles with excellent mechanical flexibility. This work provides a platform for the design and development of high-performance flexible Li–CO2 batteries from low-cost, earth-abundant, carbon-based multifunctional cathode catalysts.

Towards a stable Li–CO2 battery: The effects of CO2 to the Li metal anode

Rechargeable Li–CO2 batteries are very attractive energy storage devices because of their high theoretical energy density and unique CO2 capture capability. Unfortunately, Li metal anode is unstable to the widely used ethers-based electrolytes, and the related Coulombic efficiency is low. Here, in the ethers-based electrolyte, the effects of CO2 to the Li metal anode was studied. Using a porous electrode, the reduced CO2 will be replenished from outside upon cycling. We found that, sufficient CO2 contributed to the formation of stable solid electrolyte interface (SEI) layers and protected the Li metal anode from rapid consumption. Under a current density of 1.0 ​mA ​cm−2, the Coulombic efficiency of Li metal reached 99.0% after 200 cycles. Our work helps the researchers better understand the effects of CO2 crossover on anode and also provides a promising method to develop a stable Li metal anode for Li–CO2 battery.