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Magnetite (Fe 3 O 4) has become a potential anode material in lithium ion batteries (LIBs) because of its high theoretical capacity and low cost, but is impeded for application by its low conductivity and large volume change during cycling. Herein, the Fe 3 O 4 @C-500 composite was fabricated via the one-step pyrolytic carbonization of commercial ammonium ferric citrate (AFC), which is simple and environmentally friendly. As an anode in LIBs, the Fe 3 O 4 @C-500 electrode shows superior specific capacity, long cycling stability and excellent rate performance. Such remarkable performance can be attributed to the formation of the architecture with carbon (C) matrix, not only buffering the volume change and inhibiting the aggregation of internal Fe 3 O 4 nanoparticles during (de)lithiation, but also elevating the electron conductivity. In situ X-ray diffraction (XRD) results demonstrate that the (de)lithiated mechanism of the Fe 3 O 4 @C-500 electrode involves a full electrochemically-driven amorphization upon cycling. Furthermore, the full cell assembled with Fe 3 O 4 @C-500 and LiFePO 4 (LFP) electrodes shows outstanding electrochemical performance, demonstrating its practical energy storage application. [Display omitted] • Fe 3 O 4 @C-500 was fabricated via one-step pyrolytic carbonization of AFC. • Fe 3 O 4 @C-500 delivers good performance by nanoengineering, C matrix and amorphization. • The (de)lithiated mechanism of Fe 3 O 4 @C-500 electrode was probed by in situ XRD. • The full cell presents excellent electrochemical performances. [ABSTRACT FROM AUTHOR]

A room-temperature Ag 3 Ga-mediated liquid EGaSn anode with improved wettability for advanced Mg ion batteries. [Display omitted] • The room-temperature Ag 3 Ga-mediated liquid EGaSn anode was simply prepared for MIBs. • Ag 3 Ga can improve the wettability of EGaSn on the substrate and provide capacity. • ssm-Ag 3 Ga-EGaSn shows superior electrochemical performance in half and full cells. • Reaction mechanism of the Ag 3 Ga-mediated liquid EGaSn anode was unveiled. Liquid metals with a self-healing property can address the passivation issue of Mg metal and the huge volume variation problem of solid alloy-type anodes in rechargeable magnesium ion batteries (MIBs). Liquid Ga-based anodes show great potentials in MIBs, however, being operated at room temperature is a great challenge. Herein, a novel strategy is proposed to enhance the room-temperature Mg storage performance of liquid eutectic GaSn (EGaSn) alloy through constructing a bifunctional intermetallic compound (Ag 3 Ga) layer on the current collector. This Ag 3 Ga layer could greatly improve the wettability of EGaSn on the substrate in the electrolyte environment. Moreover, operando X-ray diffraction confirms that Ag 3 Ga could participate the reversible alloying/dealloying reactions during the discharge/charge processes and thus provide an extra capacity. Eventually, the Ag 3 Ga-mediated EGaSn anode exhibits outstanding electrochemical performance towards Mg storage in both half and full cells at room temperature (∼24 and 21 °C), as benchmarked with state-of-the-art anodes in MIBs. Specially, the MIBs could be stably cycled up to 600 cycles in the half cell configuration, and 100 cycles in the full cell assembly. This work provides useful information on the development of advanced anodes for MIBs. [ABSTRACT FROM AUTHOR]