Choe Song-Hyok, Yu Chol-Jun, Pak Yong-Chol, Choe Ye-Gyong, Jon Kwang-Il, Kim Jin-Song, Ri Kum-Chol
Chair of Computational Materials Design, Faculty of Materials Science, Kim Il Sung University, Ryongnam-Dong, Taesong District, Pyongyang, Democratic People's Republic of Korea.
Phys Chem Chem Phys. 2021 Apr 14;23(14):8456-8465. doi: 10.1039/d1cp00269d. Epub 2021 Mar 25.
Due to their low cost and easy synthesis method, several kinds of sodium titanates have been explored as anode materials for sodium ion batteries (SIBs). However, some of them have not yet been considered as electrode materials for SIBs, and here we have carried out a first-principles study on NaTiO compounds with two different tunnel structures, denoted as single and double phases, to demonstrate their structural and electrochemical properties upon Na or Li insertion. Our calculation results reveal that these compounds exhibit structural stability during sodiation/desodiation and a moderate electrode voltage of ∼0.82 V vs. Na/Na with a specific capacity of ∼150 mA h g. In particular, the activation energy of Na ion migration in the double phase is estimated to be as low as 0.28 eV, which is the lowest value among the SIB electrodes developed so far, and this can be attributed to the wide tunnel structure. In addition, we verify their potentiality for use as anode materials in lithium ion batteries (LIBs) by exploring their properties upon Li insertion. Since these compounds are predicted to be promising anode materials for SIBs or LIBs by our calculations, we believe that our findings will promote further experimental studies.
由于其低成本和简便的合成方法，几种钛酸钠已被探索用作钠离子电池（SIBs）的负极材料。然而，其中一些尚未被视为SIBs的电极材料，在此我们对具有两种不同隧道结构（分别表示为单相和双相）的NaTiO化合物进行了第一性原理研究，以展示它们在插入Na或Li时的结构和电化学性质。我们的计算结果表明，这些化合物在脱钠/嵌钠过程中表现出结构稳定性，相对于Na/Na的电极电位适中，约为0.82 V，比容量约为150 mA h g。特别地，双相中Na离子迁移的活化能估计低至0.28 eV，这是迄今为止开发的SIBs电极中的最低值，这可归因于其宽隧道结构。此外，我们通过探索它们在嵌入Li时的性质，验证了它们作为锂离子电池（LIBs）负极材料的潜力。由于我们的计算预测这些化合物有望成为SIBs或LIBs的负极材料，我们相信我们的发现将推动进一步的实验研究。
