Two‐Step Dealloying Approach to Synthesize Hierarchically Porous Nickel–Tin Alloy Toward Long‐Life Lithium‐Ion Batteries. Issue 1 (27th October 2022) - Ma, Wensheng
Abstract : 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 Al97.5 Ni2 Sn0.5 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 : The NiSn anode with interconnected ligament‐channel networks and nanowalls is fabricated by two‐step dealloying, involving corrosion of an Al97.5 Ni2 Sn0.5 precursor in NaOH and subsequent etching of Ni in HNO3 . The NiSn‐3h electrode presents excellent cycling stability with a reversible capacity of 213.9 mAh g −1 at 1 A g −1 after 1000 cycles.