Alleviating the self-discharge and enhancing the polysulphides conversion kinetics with LaCO3OH nanocrystals decorated hierarchical porous carbon

Lithium-sulfur (Li-S) batteries have been recognized as one of the most promising energy storage devices due to their ultrahigh energy density of 2600 Wh kg−1. However, their practical implementation is greatly impeded by the sluggish sulfur conversion kinetics, detrimental “shuttle effect” and severe self-discharge. In this work, LaCO3OH nanocrystals decorated nitrogen-doped carbon nanosheet arrays (MNCS-La) are fabricated via an etching-embedding method, which is further applied as an advanced sulfur reservoir for Li-S batteries. The hierarchical porous architecture of carbon nanosheet arrays provides a huge pore volume, which not only buffers the volume fluctuation of active materials during the discharge–charge process, but also facilitates the electrolyte infiltration and ion diffusion. More importantly, the monodispersed LaCO3OH nanocrystals inhibit the shuttle effect and self-discharge by forming a strong La-S bond with lithium polysulfides (LiPSs) and simultaneously enhance the electrochemical conversion kinetics. Attributed to these synergistic features, the sulfur electrodes based on MNCS-La achieve enhanced electrochemical performance, such as an initial discharge capacity of 1230 mAh/g at 0.2 C and a low capacity attenuation of 0.048% per cycle after 1000 cycles at 1 C. This work provides a feasible structural design of host for the applications of Li-S batteries and calls more attention to lanthanide metals-based composite materials.