This technology involves mixing amorphous silicon nitride (Si3N4-x) powder with a reducing agent, such as magnesium, and applying heat treatment to partially remove nitrogen. This process creates a porous silicon nitride composite in which crystalline silicon is embedded within an amorphous silicon nitride matrix.
Pure silicon anodes suffer from excessive volume expansion during charge and discharge cycles, leading to cracking, structural failure, weakened interfacial contact, and electrolyte depletion, all of which shorten battery life. Furthermore, conventional methods for producing silicon nitride, such as CVD, are limited by complex process conditions and high manufacturing costs.
This technology involves mixing amorphous silicon nitride powder and a reducing agent powder in a weight ratio of 1:0.2 to 2, followed by heat treatment at a temperature above the melting point of the reducing agent to generate crystalline silicon. Reaction byproducts such as Mg3N2 are then removed via etching to form a porous structure with 2–20 nm pores. The amorphous phase absorbs volume expansion, while the crystalline phase provides high capacity and rate capability. Applicable to high-energy lithium secondary battery anodes for electric vehicles and mass production lines for silicon-carbon composite anode materials, this technology enables the low-cost supply of long-life silicon-based anodes without the need for expensive vapor deposition equipment.
CN122719707A, WO2025-174070A1
