Huang, Q.; Wang, M.; Zhang, L.; Qi, S.; Feng, Y.; He, P.; Ji, X.; Wang, P.; Zhou, L.; Chen, S.; Wei, W.: Shear-resistant interface of layered oxide cathodes for sodium ion batteries. Energy Storage Materials 45 (2022), p. 389-398
10.1016/j.ensm.2021.11.041
Abstract:
Layered sodium transition metal (TM) oxides exhibit great potential as high energy density cathode materials for sodium-ion batteries (SIBs). The large Na ions, nevertheless, adopts various coordination environments that are dependent of the sodium concentration, giving rise to cyclical gliding of TM layers and P-O phase transitions upon Na extraction/insertion process. The detrimental interlayer-gliding induced phase transformations lead to deteriorated round-trip energy efficiency, rate capability and cycling stability of electrodes. Herein, we demonstrate a shear-resistant interface via the supersaturation of lithium to overcome the interlayer-gliding behavior and inhibit the multiple P-O phase transitions in P2-type Na0.67Mn0.67Ni0.33O2. The results indicate that the nanoscale interface is composed of lithium-enriched O3 nanodomains in the P2 phase matrix, resulting in smooth charge/discharge profiles and superior cycling stability of P2-type Na0.67Mn0.67Ni0.33O2 cathode under a high cut-off voltage of 4.5 V. This work highlights the concept of modulating the interfacial shear stress for improving the long-term cycling stability of high-voltage layered cathode materials that suffer from severe phase transformations.