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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]

Due to the high theoretical specific capacity and low cost of Sn, developing Sn‐based anode materials with long life is the key to their practical applications in lithium‐ion batteries. Herein, novel hierarchically porous NiSn alloys with interconnected ligament‐channel networks are synthesized via a two‐step dealloying strategy, involving corrosion of an Al97.5Ni2Sn0.5 precursor in NaOH, followed by partially etching Ni in HNO3. The architecture of the obtained NiSn‐3 h alloy contains the ligaments with the scale of about 115.2 nm and nanowalls with a thickness of several nanometers on the ligament surface, which can enhance the electron/ion transport kinetics and improve the tolerance to volume variation. The NiSn‐3h electrode exhibits superior Li storage performance in terms of satisfactory rate performance and excellent cycling stability with a reversible capacity of 213.9 mAh g−1 at 1 A g−1 after 1000 cycles. More importantly, the Li storage mechanism of NiSn‐3h is unveiled by operando X‐Ray diffraction, revealing the formation of lithiation products with low crystallinity at the end of discharge. In addition, on‐line differential electrochemical mass spectroscopy is used to detect the gas evolution of the NiSn‐3h electrode during the discharge–charge processes. [ABSTRACT FROM AUTHOR]

• A simple liquid Ga assisted-alloying/dealloying strategy to fabricate nanoporous Ag. • The thickness of alloy layer/nanoporous Ag varies with the mass loading of Ga. • The bimodal wire-like and unimodal bulk-like nanoporous Ag is obtained. • The substrate-supported nanoporous Ag exhibits excellent mechanical properties. The substrate-supported nanoporous Ag with controllable thickness and different morphologies (bulk-like and wire-like) is fabricated via the liquid Ga-assisted alloying/dealloying strategy. [Display omitted] Nanoporous metals show great potentials in various applications including catalysis, sensing, actuation and supercapacitors. The liquid Ga-assisted alloying/dealloying strategy is a feasible and scalable way to fabricate substrate-supported nanoporous metals. However, the influence of intrinsic alloying mode and mechanism on the formation and modulation of nanoporous structure has not been thoroughly explored before. In this work, after painting liquid Ga on Ag foil, both the bulk-like Ag 3 Ga (in the Ag-rich zone) and wire-like Ag 3 Ga (in the liquid Ga-rich zone) form owing to the interdiffusion of Ag and Ga atoms. Correspondingly, the bimodal wire-like and unimodal bulk-like nanoporous Ag is obtained because of the structure inheritance during dealloying. In addition, the thickness of alloy layer (nanoporous layer) versus mass loading of liquid Ga follows a good linear relationship. The in-situ X-ray diffraction of dealloying from Ag 3 Ga to nanoporous Ag illustrates no other intermetallic phase appears and the dealloying process can be described by the dissolution-surface diffusion model. More importantly, the substrate-supported nanoporous Ag exhibits excellent mechanical properties which are of great importance to the future applications of nanoporous metals. [ABSTRACT FROM AUTHOR]

Understanding the sodium (Na) chemistry is crucial for development of high-performance sodium ion batteries (SIBs). Nanostructured bismuth (Bi) has shown great potentials as an anode in SIBs, however, the Na storage mechanisms of Bi are still unclear. Herein, the operando X-ray diffraction (XRD) technique was utilized to probe the Na storage mechanisms of three Bi anodes (sputtered Bi film, nanoporous Bi and commercial Bi). Despite different morphologies and sizes, all the Bi anodes follow the same two-step reversible alloying/dealloying mechanisms (Bi ↔ NaBi ↔ Na 3 Bi) during the discharge/charge processes, associated with two voltage plateaus. As for the intercalation/deintercalation mechanism proposed for nanostructured Bi anodes in SIBs, we rationalize the reason why only the Bi phase is detected in the discharged/charged samples under ex-situ XRD conditions through addressing the stability issue of the Na-Bi system (NaBi and Na 3 Bi). [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]