Ma Jin, Li Chen, Ji Qianqian, Liu Chenglong, Tang Bing, Liu Ruiqi, Liu Yuying, Li Na, Wang Chao, Zeng Jianrong, Zheng Kun, Yan Wensheng
National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei, Anhui, 230029, China.
State Key Laboratory of Materials Low-Carbon Recycling, Beijing Key Laboratory of Microstructure and Properties of Solids, Beijing University of Technology, Beijing, 100124, China.
Angew Chem Int Ed Engl. 2025 Sep 4:e202513148. doi: 10.1002/anie.202513148.
The Jahn-Teller distortion caused by high-spin state Mn (t e ) is a major limiting factor for improving both the specific capacity and cycling stability of MnO cathodes in aqueous zinc-ion batteries. Thus, an intrinsic strategy for optimizing MnO involves the effective elimination of the high-spin state Mn (t e ) during electrochemical process. Herein, we focus on structural design that constructed NHVO-coated MnO (Mn@V) nanorods to achieve the low-spin state of Mn (t e ) and inhibit the Jahn-Teller distortion. The well-designed Mn@V cathode exhibits outstanding specific capacity (513.5 mAh g at 0.2 A g), remarkable rate performance (205 mAh g at 2.0 A g), and excellent cycling stability (201 mAh g after 2000 cycles at 1.0 A g). Through a series of advanced characterization techniques, such as ex-situ X-ray absorption spectroscopy, combined with theoretical calculations, we systematically demonstrate that the NHVO coating layer alters electron configuration through the V-O-Mn bridge bonds and induces the low-spin state Mn (t e ) in MnO, thereby suppressing the Jahn-Teller distortion and enhancing cycling stability. This study offers profound insights into the inhibition of the Jahn-Teller distortion from an electron spin perspective, and presents a facile approach to synergistically enhance specific capacity and cycling stability.
高自旋态Mn（t e ）引起的 Jahn-Teller 畸变是提高水系锌离子电池中MnO阴极比容量和循环稳定性的主要限制因素。因此，优化MnO的内在策略涉及在电化学过程中有效消除高自旋态Mn（t e ）。在此，我们专注于结构设计，构建了NHVO包覆的MnO（Mn@V）纳米棒，以实现Mn（t e ）的低自旋态并抑制Jahn-Teller畸变。精心设计的Mn@V阴极表现出出色的比容量（在0.2 A g时为513.5 mAh g）、卓越的倍率性能（在2.0 A g时为205 mAh g）和优异的循环稳定性（在1.0 A g下2000次循环后为201 mAh g）。通过一系列先进的表征技术，如非原位X射线吸收光谱，并结合理论计算，我们系统地证明了NHVO涂层通过V-O-Mn桥键改变电子构型，并在MnO中诱导低自旋态Mn（t e ），从而抑制Jahn-Teller畸变并提高循环稳定性。本研究从电子自旋角度对抑制Jahn-Teller畸变提供了深刻见解，并提出了一种协同提高比容量和循环稳定性的简便方法。
