Towards an ultra-long lifespan Li-CO2: electron structure and charge transfer pathway regulation on hierarchical architecture

Abstract

Lithium-CO2 batteries are recognized as an essential strategy for efficient carbon sequestration and energy storage to achieve carbon neutrality. Their cycle-ability and polarization voltage, however, are hindered by high decomposition voltage (≈4.3–4.5 V) of insulating Li2CO3. Herein, we report a significant advance toward the rational design of self-supporting and ultra-long cycle lifetime cathode for Li-CO2 batteries, dependence on a favorable hierarchical architecture and rich charge transfer constructed by homogeneously distributed MnO2 nanoplates rooted in the MXene surface supported by carbon paper. Detailedly, it exhibits impressive ultra-long-term stability of 1087 cycles (4348 h) with a low polarization gap (≈ 0.47 V) at a high current of 200 μA cm−2, which is outperformed by all the liquid electrolyte-based Li-CO2 batteries reported previously. Electronic structure analysis reveals that facile charge transfer occurs between catalytic surface and Li2CO3, springing from the –OH functional group (in MXene) to MnO2 by –OH⋯O hydrogen bonds, which acts as charge transfer channels, improving the metallicity of Li2CO3 and facilitating its decomposition and extending battery cyclability. This work paves an effective trajectory for the future development of highly efficient cathodes for durable metal-CO2 batteries.