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Density functional theory investigation on fast storage of sodium and potassium in Ni2TeO6 as a novel promising cathode material.
The limited availability of lithium metal resources has led to the development of sodium/potassium-ion batteries due to the abundance and low cost of sodium/potassium. However, finding suitable cathode materials with high capacity, stable cycling performance, and efficient electrochemical interface is still challenging. Herein, the honeycomb layered structures of P2-type A2Ni2TeO6 (A = Na, K) have been explored by density functional theory calculations as potential cathode materials for sodium and potassium storage. The optimized results show that P2-type A2Ni2TeO6 materials have large layer spacing, which enables a good reversible intercalation and results in a stable voltage platform. The calculated open-circuit voltages of Na2Ni2TeO6 and K2Ni2TeO6 are 3.69 and 3.62 V, with theoretical capacities of 138.5 and 127.9 mAh/g, respectively. The migration energy barriers of Na and K between Ni2TeO6 layers are much lower than those of other common cathode materials, making them highly promising materials for sodium and potassium storage. The thermal stabilities of intercalated Ni2TeO6 were identified through ab initio molecular dynamics simulations, lasting 10 ps at 400 K. Overall, the theoretical results of this work identified A2Ni2TeO6 as promising cathode materials for sodium and potassium storage, which could lead to the development of efficient and economically competitive sodium/potassium-ion batteries.