Bimetallic RuNi Electrocatalyst Coated MWCNTs Cathode for an Efficient and Stable Li-CO2 and Li-CO2 Mars Batteries Performance with Low Overpotential

Ultralow Overpotential in Rechargeable Li-CO2 Batteries Enabled by Caesium Phosphomolybdate as an Effective Redox Catalyst

Rechargeable lithium-CO2 batteries are emerging as attractive energy storage devices due to their potential for high capacity and efficient CO2 reduction, making them promising candidates for post-lithium-ion batteries with high energy densities. However, their practical applications have been restricted by low reversibility, poor cycle life, and sluggish redox kinetics induced by the high potential required for decomposing the discharge product Li2CO3. Despite the various cathode catalysts explored, their application is often limited by availability, high cost, and complexity of synthesis. Herein, caesium phosphomolybdate (CPM) is synthesized through a facile and low-cost method. The Li‒CO2 battery based on the CPM cathode demonstrates a high discharge capacity of 15 440 mAh g-1 at 50 mA g-1 with 97.3% coulombic efficiency. It further exhibits robust stability, operating effectively over 100 cycles at 50 mA g-1 with a capacity limitation of 500 mAh g-1. Remarkably, the CPM catalyst yields a low overpotential of 0.67 V, surpassing most catalysts reported in prior research. This study reports, for the first time, the application of a Keggin-type polyoxometalate as a bifunctional redox catalyst, significantly improving the reversible cycling of rechargeable Li-CO2 batteries.

Photo-Energized MoS2/CNT Cathode for High-Performance Li-CO2 Batteries in a Wide-Temperature Range

Li-CO2 batteries are considered promising energy storage systems in extreme environments such as Mars; however, severe performance degradation will occur at a subzero temperature owning to the sluggish reaction kinetics. Herein, a photo-energized strategy adopting sustainable solar energy in wide working temperature range Li-CO2 battery was achieved with a binder-free MoS2/carbon nanotube (CNT) photo-electrode as cathode. The unique layered structure and excellent photoelectric properties of MoS2 facilitate the abundant generation and rapid transfer of photo-excited carriers, which accelerate the CO2 reduction and Li2CO3 decomposition upon illumination. The illuminated battery at room temperature exhibited high discharge voltage of 2.95 V and mitigated charge voltage of 3.27 V, attaining superior energy efficiency of 90.2% and excellent cycling stability of over 120 cycles. Even at an extremely low temperature of - 30 °C, the battery with same electrolyte can still deliver a small polarization of 0.45 V by the photoelectric and photothermal synergistic mechanism of MoS2/CNT cathode. This work demonstrates the promising potential of the photo-energized wide working temperature range Li-CO2 battery in addressing the obstacle of charge overpotential and energy efficiency.

Approaching Splendid Catalysts for Li-CO2 Battery from the Theory to Practical Designing: A Review

Lithium carbon dioxide (Li-CO2) batteries, noted for their high discharge voltage of approximately 2.8 V and substantial theoretical specific energy of 1876 Wh kg-1, represent a promising avenue for new energy sources and CO2 emission reduction. However, the practical application of these batteries faces significant hurdles, particularly at high current densities and over extended cycle lives, due to their complex reaction mechanisms and slow kinetics. This paper delves into the recent advancements in cathode catalysts for Li-CO2 batteries, with a specific focus on the designing philosophy from composition, geometry, and homogeneity of the catalysts to the proper test conditions and real-world application. It surveys the possible catalytic mechanisms, giving readers a brief introduction of how the energy is stored and released as well as the critical exploration of the relationship between material properties and performances. Specifically, optimization and standardization of test conditions for Li-CO2 battery research is highlighted to enhance data comparability, which is also critical to facilitate the practical application of Li-CO2 batteries. This review aims to bring up inspiration from previous work to advance the design of more effective and sustainable cathode catalysts, tailored to meet the practical demands of Li-CO2 batteries.

Metal-Free Electron Donor-Acceptor Pair Enabled Long-Term Stability of Li-CO2 Battery

The challenges of Lithium-carbon dioxide (Li-CO2) batteries for ensuring long-term cycling stability arise from the thermodynamically stable and electrically insulating discharge products (e.g., Li2CO3), which primarily rely on their interaction with the active materials. To achieve the optimized intermediates, the bifunctional electron donor-acceptor (D-A) pairs are proposed in cathode design to adjust such interactions in the case of B-O pairs. The inclusion of BC2O sites allows for the optimized redistribution of electrons via p-π conjugation. The as-obtained DO-AB pairs endow the enhanced interactions with Li+, CO2, and various intermediates, accompanied by the adjustable growth mode of Li2CO3. The shift from solvation-mediated mode into surface absorption mode in turn manipulates the morphology and decomposition kinetics of Li2CO3. Therefore, the corresponding Li-CO2 battery got twofold improved in both the capacity and reversibility. The cycling prolongs exceed 1300 h and well operates at a wide temperature range (20-50 °C) and different folding angles (0-180°). Such a strategy of introducing electron donor-acceptor pairs provides a distinct direction to optimize the lifetime of Li-CO2 battery from local structure regulation at the atomic scale, further inspiring in-depth understandings for developing electrochemical energy storage and carbon capture technologies.

Carbon nanotubes with CoNi alloy nanoparticles growing on porous carbon substrate as cathode for Li-CO2 batteries

The over-exploitation of fossil fuels and rapid industrialization has released a large number of carbon dioxide. As a major greenhouse gas, it can induce the increasing global temperature and result in environmental issues. It is an urgent necessity to reduce carbon dioxide emission and increase carbon capture, utilization and storage. Li-CO2 battery can be used for the fixation and conversion of carbon dioxide to electrochemical energy. However, it is necessary to explore and design efficient catalysts, due to the low electronic conductivity and sluggish decomposition kinetics for lithium carbonate as the discharge product. Herein, carbon nanotubes with CoNi alloy nanoparticles growing on porous carbon substrate (PC/CoNi-CNTs) is designed by immersing porous melamine formaldehyde sponge into cobalt nitrate and nickel chloride solution with the subsequent carbonization. The porous structure of carbon substrate facilitates the electrolyte infiltration and carbon dioxide diffusion. The carbon nanotubes and CoNi alloy catalysts can efficiently enhance the reversible deposition and decomposition of lithium carbonate and carbon, taking advantage of their synergistic effect. At a current density of 0.05 mA cm-2, the terminal discharge and charge voltages are 2.76 and 4.23 V with a limited specific capacity of 0.2 mA h cm-2, respectively. These results demonstrat that the design of carbon nanotubes with alloy nanoparticles on porous carbon substrate as cathode can enhance the electrochemical performances of Li-CO2 battery.

Porous Carbon Foam with Carbon Nanotubes as Cathode for Li-CO2 Batteries

With the extensive use of fossil fuels, the ever-increasing greenhouse gas of mainly carbon dioxide emissions will result in global climate change. It is of utmost importance to reduce carbon dioxide emissions and its utilization. Li-CO2 batteries can convert carbon dioxide into electrochemical energy. However, developing efficient catalysts for the decomposition of Li2 CO3 as the discharge product represents a challenge in Li-CO2 batteries. Herein, we demonstrate a carbon foam composite with growing carbon nanotube by using cobalt as the catalyst, showing the ability to enhance the decomposition rate of Li2 CO3 , and thus improve the electrochemical performance of Li-CO2 batteries. Benefiting from its abundant pore structure and catalytic sites, the as-assembled Li-CO2 battery exhibits a desirable overpotential of 1.67 V after 50 cycles. Moreover, the overpotentials are 1.05 and 2.38 V at current densities of 0.02 and 0.20 mA cm-2 , respectively. These results provide a new avenue for the development of efficient catalysts for Li-CO2 batteries.