An Inorganic-Rich SEI Layer by the Catalyzed Reduction of LiNO3 Enabled by Surface-Abundant Hydrogen Bonding for Stable Lithium Metal Batteries.

Lithium (Li) metal anodes (LMAs) are promising anode candidates for realizing high-energy-density batteries. However, the formation of unstable solid electrolyte interphase (SEI) layers on Li metal is harmful for stable Li cycling; hence, enhancing the physical/chemical properties of SEI layers is important for stabilizing LMAs. Herein, thiourea (TU, CH4 N2 S) is introduced as a new catalyzing agent for LiNO3 reduction to form robust inorganic-rich SEI layers containing abundant Li3 N. Due to the unique molecular structure of TU, the TU molecules adsorb on the Cu electrode by forming CuS bond and simultaneously form hydrogen bonding with other hydrogen bonds accepting species such as NO3 - and TFSI- through its NH bonds, leading to their catalyzed reduction and hence the formation of inorganic-rich SEI layer with abundant Li3 N, LiF, and Li2 S/Li2 S2 . Particularly, this TU-modified SEI layer shows a lower film resistance and better uniformity compared to the electrochemically and naturally formed SEI layers, enabling planar Li growth without any other material treatments and hence improving the cyclic stability in Li/Cu half-cells and Li@Cu/LiFePO4  full-cells.

Realization of a 594 Wh kg-1 Lithium-Metal Battery Using a Lithium-Free V2 O5 Cathode with Enhanced Performances by Nanoarchitecturing.

To realize a high-energy lithium metal battery (LMB) using a high-capacity Li-free cathode, in this work, nanoplate-stacked V2 O5 with dominantly exposed (010) facets and a relatively short [010] length is proposed to be used as a cathode. The V2 O5 nanostructure can be fabricated via a modified hydrothermal method, including a Li+ crystallization inhibitor, followed by heat treatment. In particular, the enlargement of the favorable Li+ diffusion pathway in the [010] direction and the formation of a robust hierarchical nanoplate-stacked structure in the modified V2 O5 improves the electrochemical kinetics and stability; as a result, the nanoplate-stacked V2 O5 electrode exhibits a higher capacity and rate performance (258 mAh g-1 at 50 mA g-1 [0.17 C], 140 mAh g-1 at 1 A g-1 [3.4 C]) and cycling capability (79% capacity retention after 100 cycles at 0.5 C) compared to the previously reported V2 O5 nanobelt electrode. Notably, the LMB composed of Li//nanoplate-stacked V2 O5 full-cells shows high specific energy densities of 594.1 and 296.2 Wh kg-1 at 0.1 and 1.0 C, respectively, and a high Coulombic efficiency of 99.6% during 50 cycles.