Constructing stable lithium metal anodes using a lithium adsorbent with a high Mn3+/Mn4+ ratio

Abstract

Lithium (Li) metal batteries (LMBs) have emerged as the most prospective candidates for post-Li-ion batteries. However, the practical deployment of LMBs is frustrated by the notorious Li dendrite growth on hostless Li metal anodes. Herein, a protonated Li manganese (Mn) oxide with a high Mn3+/Mn4+ ratio is used as a Li adsorbent for constructing highly stable Li metal anodes. In addition to the Mn3+ sites with high Li affinity that afford an ultralow Li nucleation overpotential, the decrease in the average Mnn+ oxidation state also induces a disordered adsorbent structure via the Jahn-Teller effect, resulting in improved Li transfer kinetics with a significantly reduced Li electroplating overpotential. Based on the mutually improved Li diffusion and adsorption kinetics, the Li adsorbent is used as a versatile host to enable dendrite-free and stable Li metal anodes in LMBs. Consequently, a modified Li||LiNi0.8Mn0.1Co0.1O2 (NMC811) coin cell with a high NMC811 loading of 4.3 mAh cm-2 delivers a high Coulombic efficiency of 99.85% over 200 cycles and the modified Li||NMC811 pouch cell also achieves a remarkable improvement in electrochemical performance. This work demonstrates a novel approach for the preparation of highly efficient Li protection structures for safe LMBs with long lifespans.

Defect-induced-reduced Au quantum Dots@MXene decorated separator enables lithium-sulfur batteries with high sulfur utilization

“…Lithium-sulfur (Li-S) batteries have been considered as potential electrochemical energy storage systems due to their high theoretical energy density (2,600 Wh kg -1 ), which is about seven times higher than that of LiCoO 2 /graphite batteries (387 Wh kg -1 ) [1][2][3] . Moreover, sulfur is low-cost, eco-friendly, and naturally abundant.…”

Optimal Interfacial Model between the Alloy Surface and Electrolyte Solvation Structure for a Stable Lithium Metal Electrode

“…Despite the tremendous in situ/ex situ strategies to enhance the SEI strength by film-forming additives or inorganic/organic artificial coating, − fundamentally improving the Li electroplating kinetics is always a desire for achieving long-lasting stable Li metal anodes. The latter issue is mainly addressed through two aspects: (i) using high-surface-area conducting scaffolds to host the electroplated Li, where the uneven distribution of a space charge electric field that promotes dendrite growth can be alleviated by the delocalized current density; − (ii) using lithiophilic materials to decorate the Li plating substrate, where the much lowered nucleation energy barrier can mediate the Li deposition with high uniformity. − In view of the great effect to suppress dendrite and reduce cell polarization, designing lithiophilic electrode surfaces has been widely investigated by the scientific community for Li protection during the recent years, where the alloy materials possessing a high solid solubility with Li, such as Sn, Au, and Ag, are recognized as one class of the most efficacious lithiophilic materials. However, after a vast exploration of the alloy-based structures for Li protection, further progress stagnated.…”