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Electrode interfacial degradations are the key challenges for high-performance rechargeable batteries, usually mitigated through surface modification/coating strategies. Herein, we report a novel mechanism to enhance the surface stability of P2 layered cathodes by introducing a high density of dopant-enriched precipitates. Based on microscopic analysis, we show that forming a high density of precipitates at the grain surface can effectively suppress surface cracking and corrosion, which not only improves the surface/interface stability but also effectively suppresses the intergranular cracking issue. Increasing the doping level can lead to a greater density of precipitates at the surface region, which results in higher surface stability and increased cycling stability of the P2 layered cathode for a sodium-ion battery. We further reveal that prolonged cycling can induce the formation of a precipitate-free surface region due to the loss of Zn dopant and Na. Our in-depth microanalysis reveals cycling-induced dynamic structural evolution of the P2 layered cathodes, highlighting that dopant segregation-induced precipitation is a new approach to achieving high interfacial stability.
Wang et al. (2022) studied this question.