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Germanium (Ge) has become a promising anode material for lithium-ion batteries (LIBs) due to its high theoretical capacity and decent electron/ion conductivity, but it exhibits inferior lifespan caused by dramatic volume variations during the (de)lithiation process. Herein, hierarchically, nanoporous Ge (np-Ge) was fabricated by the combination of selective phase corrosion with chemical dealloying. As an anode for LIBs, the np-Ge electrode exhibits marvelous cycling stability with capacity retentions of 1060.0 mA h g−1 at 0.2 A g−1 and 767.1 mA h g−1 at 1 A g−1 after 100 cycles. Moreover, the electrode shows excellent rate capability with a capacity retention of 844.2 mA h g−1 at 5 A g−1. Noticeably, the (de)lithiation mechanisms of np-Ge and porous Si–Ge (p-Si6Ge4) were unveiled by operando X-ray diffraction. [ABSTRACT FROM AUTHOR]

Low electronic conductivity and drastic volume change during cycling of transition metal oxides, as anodes for lithium ion batteries (LIBs), lead to rapid capacity decay and poor structural stability. Herein, nanostructured NiCo 2 O 4 anchored on carbon sheets was synthesized by a facile hydrothermal method with following thermal treatment. The wrinkled carbon substrate in the composite derives from the carbonization of pomelo peels, which can be mass-produced for the large-scale application. This composite shows mesoporous structures with high specific surface areas and intimate NiCo 2 O 4 /carbon interfaces, which favors the alleviation of the volume expansion/shrink during charging/discharging process and improves the electron/mass transport, enhancing the capability and stability for LIBs. This composite delivers a high reversible capacity of 473.7 mA h g−1 after 210 cycles at a current density of 500 mA g−1. A long cycle life of up to 1100 cycles at 2000 mA g−1 is achieved with the retention capacity of 363 mA h g−1. The electrode also exhibits excellent rate capability and can regain its original capacities as reversing to the low current densities. This work highlights the biomass-derived carbon-supported metal oxides as an environmentally friendly and economic strategy for advanced LIBs. • Carbon substrate as buffer for anode materials can be derived from pomelo peels. • Cycling stability of NiCo 2 O 4 is improved by depositing it on carbon substrate. • Faster Li+ diffusion coefficients are obtained with the existence of carbon. [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]

A self-healing room-temperature liquid eutectic GaSn anode with improved wettability for advanced Mg ion batteries. [Display omitted] • ∙ Self-healing room-temperature liquid EGaSn anodes were simply prepared for MIBs. • ∙ The wettability of liquid EGaSn on ssm-CuGa 2 substrate was significantly improved. • ∙ The ssm-CuGa 2 -EGaSn shows greatly enhanced cycling stability and rate performance. • ∙ Reaction mechanism and self-healing feature of liquid EGaSn anodes were unveiled. Using alloy-type anodes offers an effective method to address the incompatibility issue between Mg metal anodes and conventional electrolytes and also facilitates the development of high performance magnesium ion batteries (MIBs). But the huge volume variations of alloy-type anodes during cycling impair the electrochemical performance of MIBs. Herein, a liquid eutectic GaSn (EGaSn) electrode with a low melting point (20.5 °C) and self-healing property was fabricated through simply painting onto stainless steel mesh (ssm). But the ssm-EGaSn electrode shows unsatisfactory electrochemical performance due to poor wettability of liquid EGaSn on ssm. To overcome this problem, a CuGa 2 layer was constructed to enhance the wettability of liquid EGaSn on the ssm substrate. The modified liquid EGaSn electrode delivers much better electrochemical performance (specific capacity, cycling stability and rate performance) either at ∼ 38 or 28 °C. Furthermore, operando X-ray diffraction and ex situ scanning electron microscopy were conducted to reveal the Mg storage mechanism and self-healing feature of the liquid EGaSn electrode. Noticeably, the liquid EGaSn electrode displays well compatibility with simple Mg salt electrolytes like Mg(TFSI) 2 and the full cell could display stable electrochemical behavior over dozens of cycles. [ABSTRACT FROM AUTHOR]

• Nanoporous NiSb (np-NiSb) alloy was fabricated by a facile dealloying strategy. • The np-NiSb anode exhibits good cycling stability and superior rate capability. • Operando XRD reveals the sodiation/desodiation mechanism of the np-NiSb anode. • On-line DEMS verifies the gas release of half cells with NiSb anode during cycling. Engineering Sb-based anode materials is the key to enhance their electrochemical performance for sodium ion batteries (SIBs) by solving the issues of the rapid capacity decay and poor rate capability. In this work, a nanoporous NiSb alloy (np-NiSb) with a three-dimensionally interconnected ligament-channel structure was synthesized by a facile dealloying strategy. As an anode for SIBs, the np-NiSb alloy exhibits excellent cycling performance, rate capability and stability with a reversible capacity of 334.6 mAh g −1 at 0.2 A g −1 after 100 cycles, 155.6 mAh g −1 at 20 A g −1 and a capacity retention rate of 97% after 100 cycles at 1 A g −1. The nanoporous structure and the introduction of inactive Ni effectively tolerate the dramatic volume changes during the charge/discharge processes, restraining the pulverization of np-NiSb. The unique ligament-channel network structure with an average size of about 30 nm significantly shortens the ion transmission distance, ensuring the fast charge transfer at high rates. Operando X-ray diffraction reveals the sodiation/desodiation mechanism of the np-NiSb anode during the discharge/charge processes. In addition, on-line differential electrochemical mass spectrometry further explores the reaction mechanism of np-NiSb. This work highlights constructing nanoporous Sb-based alloys as an effective strategy to improve the performance of SIBs. [Display omitted] As an anode for SIBs, the np-NiSb alloy with bicontinuous ligament-channel structure exhibits good cycling stability with capacity retention rate of 97% over 100 cycles at 1 A g −1 (279.7 mAh g −1). [ABSTRACT FROM AUTHOR]