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yexuqing木虫之王 (文学泰斗)
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ve thermal expansion and oxygen-redox electrochemistry
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ve thermal expansion and oxygen-redox electrochemistry 负热膨胀和氧氧化还原电化学 ▲ 作者：Bao Qiu, Yuhuan Zhou, Haoyan Liang, Minghao Zhang, Kexin Gu, Tao Zeng, Zhou Zhou, Wen Wen, Ping Miao, Lunhua He, Yinguo Xiao, Sven Burke, Zhaoping Liu & Ying Shirley Meng ▲ 链接： https://www.nature.com/articles/s41586-025-08765-x ▲ 摘要： 由于材料的热力学和电化学性质之间错综复杂的相互作用，材料内部的结构紊乱产生了令人着迷的现象。氧氧化还原（OR）电化学提供了容量限制的突破，同时引起结构紊乱，降低了电化学可逆性。固体热膨胀的传统解释依赖于格律乃森关系，将膨胀系数与晶格的非调和性联系起来。然而，由于这种系统中未探索的动态无序-有序转变，这种范式可能不适用于OR材料。 研究者发现，OR活性材料中存在负热膨胀，其系数值为?14.4(2)× 10?6℃?1，这归因于热驱动的无序-有序转变。OR行为的调制不仅可以精确控制材料的热膨胀系数，而且为零热膨胀功能材料的设计建立了一个实用的框架。 他们还证明了材料内部结构无序的恢复也可以通过电化学驱动力来完成。通过调整截止电压，对放电电压变化的评估表明，几乎可达100%结构恢复。 这一发现为通过操作电化学过程将OR活性材料恢复到原始状态提供了一条途径，提出了一种新的缓解策略来解决电压衰减的持续挑战。 ▲ Abstract： Structural disorder within materials gives rise to fascinating phenomena, attributed to the intricate interplay of their thermodynamic and electrochemical properties. Oxygen-redox (OR) electrochemistry offers a breakthrough in capacity limits, while inducing structural disorder with reduced electrochemical reversibility. The conventional explanation for the thermal expansion of solids relies on the Grüneisen relationship, linking the expansion coefficient to the anharmonicity of the crystal lattice6. However, this paradigm may not be applicable to OR materials due to the unexplored dynamic disorder–order transition in such systems. Here we reveal the presence of negative thermal expansion with a large coefficient value of ?14.4(2)?×?10?6°C?1in OR active materials, attributing this to thermally driven disorder–order transitions. The modulation of OR behaviour not only enables precise control over the thermal expansion coefficient of materials, but also establishes a pragmatic framework for the design of functional materials with zero thermal expansion. Furthermore, we demonstrate that the reinstatement of structural disorder within the material can also be accomplished through the electrochemical driving force. By adjusting the cut-off voltages, evaluation of the discharge voltage change indicates a potential for nearly 100% structure recovery. This finding offers a pathway for restoring OR active materials to their pristine state through operando electrochemical processes, presenting a new mitigation strategy to address the persistent challenge of voltage decay. |
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