Configuration Design and Interface Reconstruction to Realize the Superior High‐Rate Performance for Sodium Layered Oxide Cathodes

A multi-dimensional lanthurization strategy is proposed to construct the surface LaCrO₃ heterostructure and create a Cr─O─La configuration for NaCrO₂. The electrified heterogeneous LaCrO₃ induces a built-in electric field to accelerate charge transfer at the interface. Meanwhile, the Cr─O─La configuration in the transition metal layer leads to a local charge aggregation, weakens the interaction between Na─O, and reduces the Na⁺ migration barrier.

Abstract

Charge transfer at the electrode/electrolyte interface and mass transfer within the electrode are the two main factors affecting the high-rate performance of O3-type layered oxide cathodes for sodium-ion batteries. Here a multidimensional lanthurization strategy is proposed to construct the surface LaCrO₃ heterostructure and create a Cr─O─La configuration for O3-type NaCrO₂. The electrified heterogeneous LaCrO₃ induces a built-in electric field to accelerate charge transfer at the interface. Meanwhile, the Cr─O─La configuration in the transition metal layer leads to local charge aggregation, weakens the interaction force between Na─O, and reduces the Na⁺ migration barrier. This strategy significantly improves the electrochemical reaction kinetics and the structural reversibility of the layered oxide cathode. As a result, the designed stoichiometric ratio Na_0.94Cr_0.98La_0.02O₂ electrode exhibits remarkable rate performance (101.8 mAh g⁻¹ at 40 C) as well as outstanding cycling stability (83.1% capacity retention at 20 C for 2000 cycles) in a half-cell, along with a competitive full battery performance (89.3% after 500 cycles at 2 C). This study provides a promising route to achieve capacity presentation and retention of layered oxide cathode materials at high-rate.