Multilayer-coating process for the synthesis of nickel-silicate composite with high Ni loading as high-rate performance lithium-ion anode material

Background

Metal silicates possess several important advantages as electrode materials for lithium-ion batteries (LIBs), including straightforward synthesis, low cost, and high thermal stability. A green synthesis routes that are capable of increasing metal loading and reducing the impact on the environment are required.

Methods

A Ni-silicate with a multilayer structure and a Ni/Si molar ratio of 0.25 is first prepared using the co-precipitation method. The as-synthesized product is then repeatedly immersed in a Ni²⁺ solution to obtain Ni-silicate with the desired Ni contents (Ni/Si molar ratio: 0.50–2.00). Finally, the resulting Ni-silicate is reconstructed by hydrothermal treatment under various temperatures (70 °C, 100 °C, 150 °C) and durations (3 h and 24 h) to obtain Ni-phyllosilicate. The effects of the hydrothermal treatment temperature, hydrothermal time, and Ni/Si ratio on the structure, morphology, and surface area of the Ni-silicate composites are examined.

Significant Findings

The Ni-silicate with a Ni/Si ratio of 1.5 has a reversible capacity of 729 mAhg^-1, which exceeds traditional graphite anodes (372 mAhg^-1). Furthermore, the material exhibits a capacity retention of up to 80 % as the current density is increased from 0.025 Ag^-1 to 0.5 Ag^-1. Thus, the synthesized Ni-silicate composite is a promising candidate material for LIB anode.