MXenes emerge as promising candidates for supercapacitors due to their tunable surface chemistry and high conductivity. However, high temperatures can accelerate MXenes oxidation when exposed to air, limiting their application in supercapacitors for extreme environment operations that require high-temperature tolerance. In this work, we propose introducing bentonite nanosheets between Ti3CNTx MXene layers to suppress the high-temperature oxidation of Ti3CNTx films via a competitive oxidation mechanism, and develope a matched self-healing solid-state bentonite-based electrolyte capable of spontaneously restoring its ionic conductivity after high-temperature dehydration. The Ti3CNTx/bentonite films demonstrate exceptionally high thermal stability at temperatures of up to 600 °C when exposed to air. The solid-state supercapacitors assembled using Ti3CNTx/bentonite films and the bentonite-based electrolyte achieve a high areal capacitance of 22.8 mF cm-2 and demonstrate high-temperature tolerance, exhibiting the ability to self-heal and recover the charge storage performance even after multiple cycles of heating to 300 °C and air cooling. This work could pave the way for the application of MXenes in high-temperature tolerant and self-healing supercapacitors with enhanced longevity.

中文翻译：

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竞争性的氧化机制赋予基于 MXene 的超级电容器耐高温和自愈能力


MXenes 因其可调的表面化学性质和高导电性而成为超级电容器的有前途的候选者。然而，当暴露在空气中时，高温会加速 MXenes 氧化，从而限制了它们在超级电容器中的应用，用于需要耐高温的极端环境操作。在这项工作中，我们提议在 Ti3CNTx MXene 层之间引入膨润土纳米片，通过竞争性氧化机制抑制 Ti3CNTx 薄膜的高温氧化，并开发一种匹配的自修复固态膨润土基电解质，能够在高温脱水后自发恢复其离子电导率。Ti3CNTx/膨润土薄膜暴露在空气中时，在高达 600 °C 的温度下表现出极高的热稳定性。使用 Ti3CNTx/膨润土薄膜和膨润土基电解质组装的固态超级电容器实现了 22.8 mF cm-2 的高面电容，并表现出耐高温性，即使在多次加热至 300 °C 和风冷循环后，也表现出自我修复和恢复电荷存储性能的能力。这项工作可以为 MXenes 在耐高温和自愈超级电容器中的应用铺平道路，并延长了使用寿命。