Pt Nanoparticles Confined in a 3D Porous FeNC Matrix as Efficient Catalysts for Rechargeable Li-CO2/O2 Batteries

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.

First Application of Nitrogen-Doped Carbon Nanosheets Derived from Lotus Leaves as the Electrode Catalyst for Li-CO2/O2 Battery

The development of Li-CO2/O2 battery with high energy density and long-term stability is urgently needed to fulfill the carbon neutralization and pollution-free environment targets. The biomass-derived heteroatom-doped carbon catalyst with the combination of high-efficiency catalytic activity and sustainable supply is a promising cathode catalyst in Li-CO2/O2 battery. Specifically, the unique morphology and mesopore structure can promote the transfer of CO2, O2, and Li+. Abundant channel pores can provide discharge products accommodation to the largest extent. Nitrogen dopant, the commonly recognized active sites in carbon, can improve the electron conductivity and accelerate the sluggish kinetic reaction. Therefore, utilizing the louts leaves as the precursor, we successfully prepare the cellular-like nitrogen-doped activated carbon nanosheets (N-CNs) through the appropriate pyrolysis carbonization method. The as-synthesized carbon nanosheets display a three-dimensional interconnecting pore structure and abundant N-dopant actives, which dramatically improve the electrochemical catalytic activity of N-CNs. The Li-CO2/O2 battery with the N-CNs cathode delivers a high discharge capacity of 9825 mAh g−1, low overpotential of 1.21 V, and stable cycling performance of 95 cycles. Thus, we carry out a facile method for N-doped carbon nanosheets preparation derived from the cheap natural biomass, which can be the effective cathode catalyst for environmental-friendly Li-CO2/O2 battery.