Hou Yan, Liu Qiong, Yang Lin, Hu Jing, Wang Zhenyu, Zhang Xinmiao, Pan Jialiang, Bai Zhengyu, Wang Haijiang, Lu Zhouguang
Collaborative Innovation Center of Henan Province for Green Manufacturing of Fine Chemicals, Key Laboratory of Green Chemical Media and Reactions Ministry of Education, School of Chemistry and Chemical Engineering, Henan Normal University, Xinxiang, Henan, 453007, China.
Department of Materials Science and Engineering, Shenzhen Key Laboratory of Interfacial Science and Engineering of Materials, Guangdong-Hong Kong-Macao Joint Laboratory for Photonic-Thermal-Electrical Energy Materials and Devices, Southern University of Science and Technology, Shenzhen, Guangdong, 518055, China.
Small. 2023 May;19(18):e2207466. doi: 10.1002/smll.202207466. Epub 2023 Feb 1.
Manganese-based Na superionic conductors (NASICONs) Na MnCr(PO ) with three-electron reaction are attractive cathode materials for sodium-ion batteries. However, the irreversible distortion of Mn local structure leads to sluggish electrode kinetics, voltage hysteresis, and poor cycling stability. Here, SiO is introduced to substitute PO to modulate the local environment of Mn to activate the redox activity and stabilize the reversibility of Na MnCr(PO ) (SiO ) (NMCP-Si). A combined experimental and theoretical investigation have been undertaken to reveal the evolution of electronic structures and Na storage properties associated with SiO substitution. The NMCP-Si exhibits much-enhanced rate capability and cycling stability, being attributed to the unique Jahn-Teller distortion (Mn ) that facilitates sodium de/insertion kinetics by optimizing the Na ion diffusion channels. This work addresses the challenge of stabilizing the structure of Mn-based NASICONs and represents a breakthrough in understanding how to improve the Na conductivity by regulating local structure.
具有三电子反应的锰基钠超离子导体（NASICONs）NaMnCr(PO₄)₃是钠离子电池有吸引力的阴极材料。然而，锰局部结构的不可逆畸变导致电极动力学迟缓、电压滞后和循环稳定性差。在此，引入SiO₄来替代PO₄，以调节锰的局部环境，激活氧化还原活性并稳定Na₃MnCr(PO₄)₃(SiO₄)₃（NMCP-Si）的可逆性。已进行了实验和理论相结合的研究，以揭示与SiO₄替代相关的电子结构演变和储钠性能。NMCP-Si表现出大大增强的倍率性能和循环稳定性，这归因于独特的 Jahn-Teller 畸变（Mn³⁺），它通过优化钠离子扩散通道促进了钠的脱嵌动力学。这项工作解决了稳定锰基NASICONs结构的挑战，并代表了在理解如何通过调节局部结构提高钠电导率方面的一个突破。
