Modulating (001) plane growth in β-Ni(OH)2 precursors: a pathway to controlling lithiation kinetics and enhancing the structural integrity of LiNiO2

Abstract

The rational design of β-Ni(OH)₂ precursors is paramount for realizing the full potential of stoichiometric LiNiO₂ (LNO) cathodes. This study demonstrates that strategically engineering the precursor's crystallographic architecture governs the synthesis kinetics, structural integrity, and ultimate electrochemical performance of LNO. By solely manipulating reactant injection intervals during co-precipitation, we modulated the preferential growth of the (001) crystal plane to create distinct β-Ni(OH)₂ microstructures. The intentional restriction of (001) plane growth yielded a precursor with a high specific surface area, which significantly lowered the activation energy for lithiation. This kinetic advantage promoted a more complete and uniform phase transformation, resulting in a final LNO cathode with larger crystallites, lower lattice strain, and superior mechanical integrity. Conversely, the dense precursor derived from promoted (001) plane growth imposed a kinetic barrier, leading to incomplete reaction, residual inactive phases, and high internal strain. These profound structural differences translated directly into electrochemical performance. The LNO derived from the engineered precursor delivered higher capacity, superior rate capability, and better cycling stability, whereas its counterpart suffered from severe particle fragmentation and rapid degradation. This work establishes a direct, causal pathway from precursor-level crystallographic engineering to structurally robust, high-performance LNO cathodes.