Tailoring Coordination in Conventional Ether-Based Electrolytes for Reversible Magnesium-Metal Anodes.

Rechargeable magnesium (Mg) batteries based on conventional electrolytes are seriously plagued by the formation of the ion-blocking passivation layer on the Mg metal anode. By tracking the Mg solvation sheath, this work links the passivation components to the Mg -solvents (1,2-dimethoxyethane, DME) coordination and the consequent thermodynamically unstable DME molecules. On this basis, we propose a methodology to tailor solvation coordination by introducing the additive solvent with extreme electron richness.

Defect-Free Metal-Organic Framework Membrane for Precise Ion/Solvent Separation toward Highly Stable Magnesium Metal Anode.

Metallic magnesium batteries are promising candidates beyond lithium-ion batteries; however, a passive interfacial layer because of the electro-reduction of solvents on Mg surfaces usually leads to ultrahigh overpotential for the reversible Mg chemistry. Inspired by the excellent separation effect of permselective metal-organic framework (MOF) at angstrom scale, a large-area and defect-free MOF membrane directly on Mg surfaces is here constructed. In this process, the electrochemical deprotonation of ligand can be facilitated to afford the self-correcting of intercrystalline voids until a seamless membrane formed, which can eliminate nonselective intercrystalline diffusion of electrolyte and realize selective Mg transport but precisely separate the solvent molecules from the MOF channels.

Ionic Liquid-Mediated Mass Transport Channels for Ultrahigh Rate Lithium-Ion Batteries.

Excellent mass transport capability is indispensable to building a high-power lithium-ion battery (LIB) system. Nanomaterials with enhanced electrochemical properties have been used for next-generation high-performance LIBs. However, due to the high surface free energy, nanomaterials tend to form agglomeration.

Three-Dimensional Magnesiophilic Scaffolds for Reduced Passivation toward High-Rate Mg Metal Anodes in a Noncorrosive Electrolyte.

Magnesium ion batteries are a promising alternative of the lithium counterpart; however, the poorly ion-conductive passivation layer on Mg metal makes plating/stripping difficult. In addition to the generally recognized chemical passivation, the interphase is dynamically degraded by electrochemical side reactions. Especially under high current densities, the interphase thickens, exacerbating the electrode degradation.

Electrostatic Shielding Guides Lateral Deposition for Stable Interphase toward Reversible Magnesium Metal Anodes.

Compared with lithium, magnesium shows a low propensity toward dendritic deposition due to its low surface self-diffusion barriers. However, due to the intrinsic surface roughness of the metal and the nonuniformity of the formed solid-electrolyte interphase, uneven deposition of Mg still happens, which brings about high local current density and continuous proliferation of the interphase, greatly exacerbating the passivation. Unfortunately, little attention has been paid to the deposition uniformity and the interfacial stability of Mg metal anodes, which result in a potential penalty.

Decreasing Ion-Diffusion Barrier Enables Superior Na-Ion Storage by Synergizing Hierarchical Architecture and Lattice Distortion.

Compared with nanosized materials, the long-pathway isolation of the interior part from the electrolyte for bulk electrode materials may result in high ionic diffusion barrier, leading to the poor rate behavior. Either the modification of lattice or the construction of a porous structure is generally effective to decrease the ion-diffusion barrier; however, achieving these multiscaled modulations simultaneously via a facile approach is still a challenge. Herein, we manipulate a bifunctional dopant to prepare micron-sized NaV(PO) with extraordinary synergy of hierarchical architecture and lattice distortion.

Rational Design of the Robust Janus Shell on Silicon Anodes for High-Performance Lithium-Ion Batteries.

The high-capacity silicon anode is regarded as a promising electrode material for next-generation lithium-ion batteries. Unfortunately, its practical application is still severely hindered by electrode fracture and unstable solid electrolyte interphase during cycling. Herein, we design a structure of encapsulating silicon in a robust "janus shell", in which an internal graphene shell with sufficient void space is used to absorb the mechanical stress induced by volume expansion, and the conformal carbon outer shell is introduced to strongly bond the loosely stacked graphene shell and simultaneously seal the nanopores on the surface.