Cheng Zhiwei, Fan Xin-Yu, Yu Lianzheng, Hua Weibo, Guo Yu-Jie, Feng Yi-Hu, Ji Fang-Di, Liu Mengting, Yin Ya-Xia, Han Xiaogang, Guo Yu-Guo, Wang Peng-Fei
Center of Nanomaterials for Renewable Energy, State Key Laboratory of Electrical Insulation and Power Equipment, School of Electrical Engineering, Xi'an Jiaotong University, Xi'an, Shaanxi 710049, P.R. China.
School of Chemical Engineering and Technology, Xi'an Jiaotong University, Xi'an, Shaanxi 710049, P.R. China.
Angew Chem Int Ed Engl. 2022 May 2;61(19):e202117728. doi: 10.1002/anie.202117728. Epub 2022 Mar 11.
Layered oxide cathodes usually exhibit high compositional diversity, thus providing controllable electrochemical performance for Na-ion batteries. These abundant components lead to complicated structural chemistry, closely affecting the stacking preference, phase transition and Na kinetics. With this perspective, we explore the thermodynamically stable phase diagram of various P2/O3 composites based on a rational biphasic tailoring strategy. Then a specific P2/O3 composite is investigated and compared with its monophasic counterparts. A highly reversible structural evolution of P2/O3-P2/O3/P3-P2/P3-P2/Z/O3'-Z/O3' based on the Ni /Ni , Fe /Fe and Mn /Mn redox couples upon sequential Na extraction/insertion is revealed. The reduced structural strain at the phase boundary alleviates the phase transition and decreases the lattice mismatch during cycling, endowing the biphasic electrode a large reversible capacity of 144 mAh g with the energy density approaching 514 Wh kg .
层状氧化物阴极通常表现出高度的成分多样性，从而为钠离子电池提供可控的电化学性能。这些丰富的成分导致复杂的结构化学，密切影响堆叠偏好、相变和钠动力学。基于这一观点，我们基于合理的双相剪裁策略探索了各种P2/O3复合材料的热力学稳定相图。然后研究了一种特定的P2/O3复合材料，并将其与其单相对应物进行比较。揭示了基于Ni /Ni、Fe /Fe和Mn /Mn氧化还原对在连续钠脱嵌过程中P2/O3-P2/O3/P3-P2/P3-P2/Z/O3'-Z/O3'的高度可逆结构演变。相界处降低的结构应变减轻了相变并减少了循环过程中的晶格失配，赋予双相电极144 mAh g的大可逆容量，能量密度接近514 Wh kg 。
