Interdisciplinary Materials Science Program and ‡Department of Mechanical Engineering, Vanderbilt University , Nashville, Tennessee 37235, United States.
ACS Nano. 2017 Jun 27;11(6):6243-6251. doi: 10.1021/acsnano.7b02404. Epub 2017 Jun 9.
The interplay between mechanical strains and battery electrochemistry, or the tunable mechanochemistry of batteries, remains an emerging research area with limited experimental progress. In this report, we demonstrate how elastic strains applied to vanadium pentoxide (VO), a widely studied cathode material for Li-ion batteries, can modulate the kinetics and energetics of lithium-ion intercalation. We utilize atomic layer deposition to coat VO materials onto the surface of a shapememory superelastic NiTi alloy, which allows electrochemical assessment at a fixed and measurable level of elastic strain imposed on the VO, with strain state assessed through Raman spectroscopy and X-ray diffraction. Our results indicate modulation of electrochemical intercalation potentials by ∼40 mV and an increase of the diffusion coefficient of lithium ions by up to 2.5-times with elastic prestrains of <2% imposed on the VO. These results are supported by density functional theory calculations and demonstrate how mechanics of nanomaterials can be used as a precise tool to strain engineer the electrochemical energy storage performance of battery materials.
机械应变与电池电化学之间的相互作用，或电池的可调谐机械化学，仍然是一个新兴的研究领域，实验进展有限。在本报告中，我们展示了如何将弹性应变施加到五氧化二钒（VO）上，五氧化二钒是锂离子电池中广泛研究的阴极材料，从而调节锂离子嵌入的动力学和能量学。我们利用原子层沉积将 VO 材料涂覆在形状记忆超弹性 NiTi 合金的表面上，这使得可以在固定和可测量的弹性应变水平下对 VO 进行电化学评估，通过拉曼光谱和 X 射线衍射评估应变状态。我们的结果表明，通过对 VO 施加小于 2%的弹性预应变，可以将电化学嵌入势调制约 40 mV，并将锂离子的扩散系数提高高达 2.5 倍。这些结果得到了密度泛函理论计算的支持，并证明了如何将纳米材料力学用作精确工具来应变工程电池材料的电化学储能性能。
