High-energy-density Li-CO2 batteries are promising candidates for large-capacity energy storage systems. However, the development of Li-CO2 batteries has been hindered by low cycle life and high overpotential. In this study, we propose a CO2-based thermoplastic polyurethane (CO2-based TPU) with CO2 adsorption properties and excellent self-healing performance to replace traditional polyvinylidene fluoride (PVDF) as the cathode binder. The CO2-based TPU enhances the interfacial concentration of CO2 at the cathode/electrolyte interfaces, effectively increasing the discharge voltage and lowering the charge voltage of Li-CO2 batteries. Moreover, the CO2 fixed by urethane groups (-NH-COO-) in the CO2-based TPU are difficult to shuttle to and corrode the Li anode, minimizing CO2 side reactions with lithium metal and improving the cycling performance of Li-CO2 batteries. In this work, Li-CO2 batteries with CO2-based TPU as the multifunctional binders exhibit stable cycling performance for 52 cycles at a current density of 0.2 A g-1, with a distinctly lower polarization voltage than PVDF bound Li-CO2 batteries.

Lithium-carbon dioxide (Li-CO2 ) batteries are regarded as a prospective technology to relieve the pressure of greenhouse emissions but are confronted with sluggish CO2 redox kinetics and low energy efficiency. Developing highly efficient and low-cost catalysts to boost bidirectional activities is craved but remains a huge challenge. Herein, derived from the spent lithium-ion batteries, a tandem catalyst is subtly synthesized and significantly accelerates the CO2 reduction and evolution reactions (CO2 RR and CO2 ER) kinetics with an in-built electric field (BEF). Combining with the theoretical calculations and advanced characterization techniques, this work reveals that the designed interface-induced BEF regulates the adsorption/decomposition of the intermediates during CO2 RR and CO2 ER, endowing the recycled tandem catalyst with excellent bidirectional activities. As a result, the spent electronics-derived tandem catalyst exhibits remarkable bidirectional catalytic performance, such as an ultralow voltage gap of 0.26 V and an ultrahigh energy efficiency of 92.4%. Profoundly, this work affords new opportunities to fabricate low-cost electrocatalysts from recycled spent electronics and inspires fresh perceptions of interfacial regulation including but not limited to BEF to engineer better Li-CO2 batteries.

Li-CO2 batteries arouse great interest in the context of carbon neutralization, but their practicability is severely hindered by the sluggish CO2 redox reaction kinetics at the cathode, which brings about formidable challenges such as high overpotential and low Coulombic efficiency. For the complex multi-electron transfer process, the design of catalysts at the molecular or atomic level and the understanding of the relationship between electron state and performance are essential for the CO2 redox. However, little attention is paid to it. In this work, using Co3 S4 as a model system, density functional theory (DFT) calculations reveal that the adjusted d-band and p-band centers of Co3 S4 with the introduction of Cu and sulfur vacancies are hybridized between CO2 and Li species, respectively, which is conducive to the adsorption of reactants and the decomposition of Li2 CO3 , and the experimental results further verify the effectiveness of energy band engineering. As a result, a highly efficient bidirectional catalyst is produced and shows an ultra-small voltage gap of 0.73 V and marvelous Coulombic efficiency of 92.6%, surpassing those of previous catalysts under similar conditions. This work presents an effective catalyst design and affords new insight into the high-performance cathode catalyst materials for Li-CO2 batteries.

Lithium-carbon dioxide (Li-CO2 ) battery technology presents a promising opportunity for carbon capture and energy storage. Despite tremendous efforts in Li-CO2 batteries, the complex electrode/electrolyte/CO2 triple-phase interfacial processes remain poorly understood, in particular at the nanoscale. Here, using in situ atomic force microscopy and laser confocal microscopy-differential interference contrast microscopy, we directly observed the CO2 conversion processes in Li-CO2 batteries at the nanoscale, and further revealed a laser-tuned reaction pathway based on the real-time observations. During discharge, a bi-component composite, Li2 CO3 /C, deposits as micron-sized clusters through a 3D progressive growth model, followed by a 3D decomposition pathway during the subsequent recharge. When the cell operates under laser (λ=405 nm) irradiation, densely packed Li2 CO3 /C flakes deposit rapidly during discharge. Upon the recharge, they predominantly decompose at the interfaces of the flake and electrode, detaching themselves from the electrode and causing irreversible capacity degradation. In situ Raman shows that the laser promotes the formation of poorly soluble intermediates, Li2 C2 O4 , which in turn affects growth/decomposition pathways of Li2 CO3 /C and the cell performance. Our findings provide mechanistic insights into interfacial evolution in Li-CO2 batteries and the laser-tuned CO2 conversion reactions, which can inspire strategies of monitoring and controlling the multistep and multiphase interfacial reactions in advanced electrochemical devices.

As a high energy density power system, lithium-carbon dioxide (Li-CO2 ) batteries play an important role in addressing the fossil fuel crisis issues and alleviating the greenhouse effect. However, the sluggish transformation kinetic of CO2 and the difficult decomposition of discharge products impede the achievement of large capacity, small overpotential, and long life span of the batteries, which require exploring efficient catalysts to resolve these problems. In this review, the main focus is on the hot spot regulation strategies of the catalysts, which include the modulation of the active sites, the designing of microstructure, and the construction of composition. The recent progress of promising catalysis with hot spot regulated strategies is systematically addressed. Critical challenges are also presented and perspectives to provide useful guidance for the rational design of highly efficient catalysts for practical advanced Li-CO2 batteries are proposed.

Li-CO2 batteries that integrate energy storage with greenhouse gas fixation have received a great deal of attention in the pursuit of carbon neutrality. However, cyclic accumulation of the insulative and insoluble Li2CO3 on the cathode surface severely restrains the battery cyclability, especially under a high depth of discharge/charge. Herein, we design and fabricate a microreactor-type catalyst by embedding Ru nanoparticles into the shells of mesoporous hollow carbon spheres. We show that both the hollow cavity and mesoporous shell are indispensable for concertedly furnishing a high activity to catalyze reversible Li2CO3 formation/decomposition. This unique structure ensures that the Ru sites masked by exterior Li2CO3 deposits during charging can resume the redox process of discharge by working with the prestored electrolyte to establish an inner reaction path. The thus fabricated Li-CO2 batteries demonstrate remarkable cyclability of 1085 cycles under 0.5 Ah g-1 and 326 cycles under 2 Ah g-1 at 1 A g-1, outshining most of the literature reports. This study highlights a smart catalyst design to boost the reversibility and cyclability of Li-CO2 batteries through an \"in & out\" strategy.

Li-CO2 battery with high energy density has aroused great interest recently, large-scale applications are hindered by the limited cathode catalysis performance and execrably cycle performance. Herein, Mo3 P/Mo Mott-Schottky heterojunction nanorod electrocatalyst with abundant porous structure is fabricated and served as cathodes for Li-CO2 batteries. The Mo3 P/Mo cathodes exhibit ultra-high discharge specific capacity of 10 577 mAh g-1 , low polarization voltage of 0.15 V, and high energy efficiency of up to 94.7%. Mott-Schottky heterojunction formed by Mo and Mo3 P drives electron transfer and optimizes the surface electronic structure, which is beneficial to accelerate the interface reaction kinetics. Distinctively, during the discharge process, the C2 O4 2- intermediates combine with Mo atoms to form a stable Mo-O coupling bridge on the catalyst surface, which effectively facilitate the formation and stabilization of Li2 C2 O4 products. In addition, the construction of the Mo-O coupling bridge between the Mott-Schottky heterojunction and Li2 C2 O4 promotes the reversible formation and decomposition of discharge products and optimizes the polarization performance of the Li-CO2 battery. This work provides another pathway for the development of heterostructure engineering electrocatalysts for high-performance Li-CO2 batteries.

The Li-CO2 battery has great potential for both CO2 utilization and energy storage, but its practical application is limited by low energy efficiency and short cycle life. Efficient cathode catalysts are needed to address this issue. Herein, this work reports on molecularly dispersed electrocatalysts (MDEs) of nickel phthalocyanine (NiPc) anchored on carbon nanotubes (CNTs) as the cathode catalyst for Li-CO2 batteries. The dispersed NiPc molecules efficiently catalyze CO2 reduction, while the conductive and porous CNTs networks facilitate CO2 evolution reaction, leading to enhanced discharging and charging performance compared to the NiPc and CNTs mixture. Octa-cyano substitution on NiPc (NiPc-CN) further enhances the interaction between the molecule and CNTs, resulting in better cycling stability. The Li-CO2 battery with the NiPc-CN MDE cathode shows a high discharge voltage of 2.72 V and a small discharging-charging potential gap of 1.4 V, and can work stably for over 120 cycles. The reversibility of the cathode is confirmed by experimental characterizations. This work lays a foundation for the development of molecular catalysts for Li-CO2 battery cathodes.

Rechargeable lithium-carbon dioxide (Li-CO2 ) batteries are promising devices for CO2 recycling and energy storage. However, thermodynamically stable and electrically insulating discharge products (DPs) (e.g., Li2 CO3 ) deposited at cathodes require rigorous conditions for completed decomposition, resulting in large recharge polarization and poor battery reversibility. Although progress has been achieved in cathode design and electrolyte optimization, the significance of DPs is generally underestimated. Therefore, it is necessary to revisit the role of DPs in Li-CO2 batteries to boost overall battery performance. Here, a critical and systematic review of DPs in Li-CO2 batteries is reported for the first time. Fundamentals of reactions for formation and decomposition of DPs are appraised; impacts on battery performance including overpotential, capacity, and stability are demonstrated; and the necessity of discharge product management is highlighted. Practical in situ/operando technologies are assessed to characterize reaction intermediates and the corresponding DPs for mechanism investigation. Additionally, achievable control measures to boost the decomposition of DPs are evidenced to provide battery design principles and improve the battery performance. Findings from this work will deepen the understanding of electrochemistry of Li-CO2 batteries and promote practical applications.

To date, the effect of noble metal (NM) electronic structures on CO2 reaction activity remains unknown, and explicit screening criteria are still lacking for designing highly efficient catalysts in CO2 -breathing batteries. Herein, by preferentially considering the decomposition of key intermediate Li2 CO3 , an intrinsic descriptor constituted of the d x 2 - y 2 ${{\\rm{d}}}_{{x}^2 - {y}^2}$ orbital states and the electronegativity for predicting high-performance cathode material are discovered. As a demonstration, a series of graphene-supported noble metals (NM@G) as cathodes are fabricated via a fast laser scribing technique. Consistent with the preliminary prediction, Pd@G exhibits an ultralow overpotential (0.41 V), along with superior cycling performance up to 1400 h. Moreover, the overall thermodynamic reaction pathways on NM@G confirm the reliability of the established intrinsic descriptor. This basic finding of the relationship between the electronic properties of noble metal cathodes and the performance of Li-CO2 batteries provides a novel avenue for designing remarkably efficient cathode materials for metal-CO2 batteries.