Deeper Understanding of the Lithiation Reaction during the Synthesis of LiNiO2 Towards an Increased Production Throughput

Abstract

Efficient manufacturing of cathode active materials (CAMs) for Li-ion batteries is one key target on the roadmap towards cost reduction and improved sustainability. This work deals with a two-stage calcination process for the synthesis of LiNiO2 (LNO) consisting of a (partial) lithiation step at moderate temperatures and short dwell times and a subsequent high temperature crystallization to decouple the chemical reactions and crystal growth. The use of an agitated-bed lithiation using the rotational movement of a rotary kiln setup shows beneficial effects compared to its fixed-bed counterpart in a crucible as the lithiation reaction is faster under otherwise comparable conditions. The temperature profile for the agitated-bed process was further optimized to avoid the presence of needle-like LiOH residuals in the intermediate product indicative of an incomplete reaction. The partially-lithiated samples were subjected to a second calcination step at a maximum calcination temperature of 700 °C and afterwards revealed comparable physico-chemical properties and electrochemical behavior compared to a reference sample made by a standard one-stage calcination. In a simplified model calculation, the proposed calcination concept leads to an increase in throughput by a factor of ∼ 3 and thus could embody an important lever for the efficiency of future CAM production.