Pseudo-negative compressibility in layered materials is a phenomenon typically limited to in situ high-pressure experiments in some clay minerals and carbon-based materials. We show that the MXene Ti₃C₂T _x expands along its crystallographic c direction when compressed in the presence of H₂O. This expansive effect occurs when a mixture of powders and excess water is quasi-hydrostatically compressed in a diamond anvil cell; it also occurs to a much larger extent when powders are pressed uniaxially into discs and, notably, persists after pressure is released. We attribute the expansion to the insertion of H₂O molecules and have identified shear-induced slipping of the nanosheets comprising multilayered MXene particles as a possible cause of this behavior in the latter case. This both has implications for the processing of MXenes and contributes to the field of materials with pseudo-negative compressibility by adding a new member for further investigation.

中文翻译：

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水存在下 Ti3C2 MXene 中压力引起的剪切和层间膨胀。

层状材料中的伪负压缩性是一种通常仅限于某些粘土矿物和碳基材料的原位高压实验的现象。_{我们表明，当在 H 2} O存在下压缩时，MXene Ti ₃ C ₂ T _x沿其晶体学c方向膨胀。当粉末和过量水的混合物在金刚石砧室中进行准流体静力学压缩时，就会发生这种膨胀效应。当粉末被单轴压入圆盘时，这种现象也会在更大程度上发生，并且值得注意的是，在压力释放后，这种现象仍然存在。我们将膨胀归因于 H ₂ O 分子的插入，并发现包含多层 MXene 颗粒的纳米片的剪切诱导滑动是后一种情况下这种行为的可能原因。这既对 MXene 的加工产生影响，又通过添加新成员进行进一步研究，为伪负压缩材料领域做出了贡献。