Rechargeable magnesium batteries (RMBs) have attracted significant attention owing to the high energy density and economic viability. However, the lack of suitable cathode materials, owing to the high polarizability of divalent Mg-ion and slow Mg-ion diffusion, hinders the development of RMBs. V 2 O 5 is a promising RMBs cathode material, but its limited interlayer spacing is unfavorable for the rapid diffusion of Mg 2 + , demonstrating unsatisfactory electrochemical performance. In this study, the superlattices of V 2 O 5 and polyaniline (PANI) with expanded interlayer spacing are assembled as the cathode material for RMBs. The intercalation of PANI in the interlayer region of V 2 O 5 significantly improves the reversible capacities, Mg 2 + diffusion kinetics, and cycling performance of the PVO cathode. Furthermore, RMBs with PVO as the cathode and Mg metal as the anode deliver high specific capacities. The introduced polyaniline layer not only expands the interlayer spacing of V 2 O 5 , but also increases the electrical conductivity. Moreover, ex situ XRD characterization indicates that PVO does not undergo obvious phase transformation with the continuous insertion of Mg 2 + , which may be ascribed to the π-conjugated chains of PANI that give flexibility to the structure to improve cycling stability. This study demonstrates that designing organic-inorganic superlattices is an efficient strategy for developing high-performance cathode materials for RMBs.

Incompatible interphases resulting from the irreconcilable contradiction between impedance and mechanical strength have become one of the major obstacles to the practical application of solid-state lithium metal batteries (SSLMBs). With the employment of a decoupling strategy by rational topological design, herein a topological polymer-reinforced interphase layer is in situ constructed using a synthesized solid polymer electrolyte. As a result, the constructed topological solid electrolyte interphase (SEI) layer harmonizes the enhanced mechanochemical stability and fast diffusion dynamics of Li + , which maintains the integrity and stability of the SEI layer during cycling. In addition, a highly stable and reversible Li nucleation/stripping behaviors exceeding 3000 h and the superior cycling performance of practical LiFePO 4 /Li metal battery beyond 500 cycles can be achieved by virtue of the formation of the topological interphase layer. This design strategy of constructing a topological interphase layer to decouple mechanical strength and the activation energy of Li + transport provides a feasible paradigm for realizing practical SSLMBs.

No abstract

No abstract

Exploring promising electrolyte‐system with high reversible Mg plating/stripping and excellent stability is essential for rechargeable magnesium batteries (RMBs). Fluoride alkyl magnesium salts (Mg(ORF)2) not only possess high solubility in ether solvents but also compatible with Mg metal anode, thus holding a vast application prospect. Herein, a series of diverse Mg(ORF)2 were synthesized, among them, perfluoro‐tert‐butanol magnesium (Mg(PFTB)2)/AlCl3/MgCl2 based electrolyte demonstrates highest oxidation stability, and promotes the in situ formation of robust solid electrolyte interface. Consequently, the fabricated symmetric cell sustains a long‐term cycling over 2000 h, and the asymmetric cell exhibits a stable Coulombic efficiency of 99.5 % over 3000 cycles. Furthermore, the Mg||Mo6S8 full cell maintains a stable cycling over 500 cycles. This work presents guidance for understanding structure–property relationships and electrolyte applications of fluoride alkyl magnesium salts.