Unique Hierarchically Structured High-Entropy Alloys with Multiple Adsorption Sites for Rechargeable Li-CO2 Batteries with High Capacity.

Lithium-carbon dioxide (Li-CO2) batteries offer the possibility of synchronous implementation of carbon neutrality and the development of advanced energy storage devices. The exploration of low-cost and efficient cathode catalysts is key to the improvement of Li-CO2 batteries. Herein, high-entropy alloys (HEAs)@C hierarchical nanosheet is synthesized from the simulation of the recycling solution of waste batteries to construct a cathode for the first time. Owing to the excellent electrical conductivity of the carbon material, the unique high-entropy effect of the HEAs, and the large number of catalytically active sites exposed by the hierarchical structure, the FeCoNiMnCuAl@C-based battery exhibits a superior discharge capability of 27664 mAh g-1 and outstanding durability of 134 cycles as well as low overpotential with 1.05 V at a discharge/recharge rate of 100 mA g-1. The adsorption capacity of different sites on the HEAs is deeply understood through density functional theory calculations combined with experiments. This work opens up the application of HEAs in Li-CO2 batteries catalytic cathodes and provides unique insights into the study of adsorption active sites in HEAs.

Achieving Sustainable and Stable Potassium-Ion Batteries by Leaf-Bioinspired Nanofluidic Flow.

In nature, living systems have evolved integrated structures, matching optimized nanofluidics to adapt to external conditions. In rechargeable batteries, high-capacity electrodes are often plagued by the crucial and universal bottleneck of dissolution and shuttle of active substance into electrolyte, posing obstacles of inevitable capacity degradation. Introducing the concept of intelligent nanofluidics to electrodes, a leaf-bioinspired electrode configuration with hierarchical architecture to tackle this problem is proposed. This integrated structure with fine-tuned surface pores and unobstructed interior porous media, can spatially control the anisotropic nanofluidic flux, in an efficient and self-protectable way: tailoring the outflow across the electrode's surface and free transport in interior, to ensure speedy and stable energy conversion. As proofs of concept, applications of sustainable electrodes rejuvenated from fallen leaf and spent commercial batteries, are designed with leaf-bioinspired architecture. Both KCoS2 and KS battery systems show advanced steady cycling with effectively mitigated shuttle issues in this smart architecture (0.15% and 0.21% capacity decay per cycle), even at high areal mass loading, when compared with open porous structure (0.60% and 0.39%). This work may pave a new way from a biomimetic view to integrated electrode engineering with regulated surface shielding to conquer the universal dissolution-shuttle problems facing high-capacity materials.