Synthesis of Ni@NiSn Composite with High Lithium‐Ion Diffusion Coefficient for Fast‐Charging Lithium‐Ion Batteries

Abstract

Abstract To solve the problems of fast‐charging of lithium‐ion batteries in essence, development of new electrode materials with higher lithium‐ion diffusion coefficients is the key. In this work, a novel flower‐like Ni@SnNi structure is synthesized via a two‐step process design, which consists of the fabrication of Ni cores by spray pyrolysis followed by the formation of SnNi shells via a simple oxidation–reduction reaction. The obtained Ni@SnNi composite exhibits an initial capacity of ≈693 mA h g−1 and a reversible capacity of ≈570 mA h g−1 after 300 charge/discharge cycles at 0.5 C, and maintains 450 mA h g−1 even at a high rate of 3 C. Further, it is proved that a Ni@SnNi composite possesses high lithium‐ion diffusion coefficient (≈10−8), which is much higher than those (≈10−10) reported previously, which can be mainly attributed to the unique flower‐like Ni@SnNi structure. In addition, the full cell performance (Ni@SnNi‐9h/graphite vs LiCoO2) with a capacity ratio of 1.13 (anode/cathode) is also tested. It is found that even at 2 C rate charging/discharging, the capacity retention at 100 cycles is still close to 89%. It means that Ni@SnNi‐9h is a promising anode additive for lithium‐ion batteries with high energy density and power density.

Keywords

• fast‐charging
• ion diffusion coefficient
• lithium ion batteries
• Ni@NiSn composite
• Sn–Ni