MXene-BN-Introduced Artificial SEI to Inhibit Dendrite Growth of Lithium Metal Batteries.

Lithiophilic substrates have been shown to improve the electrochemical performance of lithium metal anodes. The MXene-BN/Cu 3D current collector was prepared by a filtration method. The artificial solid electrolyte interface (SEI) layer composed of Li3N and LiF was formed on the surface of MXene-BN/Cu during the Li deposition process. Volume changes can be effectively relieved by this special 3D structure. The artificial SEI film reduced the critical dendrite growth length, inhibited Li dendrite growth, and stabilized the electrochemical cycle. MXene-BN/Cu exhibited highly reversible cycling properties during lithium metal deposition with a high Coulombic efficiency of ∼ 98.0% over 500 cycles. Furthermore, LiBH4 was produced during the Li deposition process. This study presents a promising strategy for developing dendrite-free Li anodes for use in lithium metal batteries.

High-loading LiBH4 Confined in Structurally Tunable Ni Catalyst-decorated Porous Carbon Scaffold for Fast Hydrogen Desorption.

Catalysts combined with nanoconfinement can improve the sluggish desorption kinetics and poor reversibility of LiBH4 . However, at high LiBH4 loading, their hydrogen storage performance is significantly reduced. Herein, a porous carbon-sphere scaffold decorated with Ni nanoparticles (NPs) was synthesised by calcining a Ni metal-organic framework precursor, followed by partial etching of the Ni NPs to fabricate an optimised scaffold with a high surface area and large porosity that accommodates high LiBH4 loading (up to 60 wt.%) and exhibits remarkable catalyst/nanoconfinement synergy. Owing to the catalytic effect of Ni2 B (formed in situ during dehydrogenation) and the reduced hydrogen diffusion distances, the 60 wt.% LiBH4 confined system exhibited enhanced dehydrogenation kinetics with >87% of the total hydrogen storage capacity released within 30 min at 375 °C. The apparent activation energies were significantly reduced to 110.5 and 98.3 kJ/mol, compared to that of pure LiBH4 (149.6 kJ/mol). Moreover, partial reversibility was achieved under moderate conditions (75 bar H2 , 300 °C) with rapid dehydrogenation during cycling.