电池材料比较应通过最佳实践重新聚焦扩散率
Battery Material Comparisons Should Refocus on Diffusivity with Best Practices
AI总结：
研究基于对改进电池的需求，主张重新聚焦电池材料扩散率比较。通过审查相关文献发现问题，比较多种测量方法及错误陷阱，以实例展示不同制备方法材料的扩散率与电池性能差异，强调最佳实践对材料开发中结构 - 属性关系研究的重要性。
AI中文摘要：
对改进电池的持续需求推动了具有改善传输性能材料的发现和进步。离子扩散率是相关材料属性，其测量取决于对活性材料长度尺度的准确评估，通常来自质量比表面积。本文主张重新关注扩散率比较。对303篇近期关于电池材料开发的开放获取出版物的程序审查发现：49%的出版物用扩散率值支持结构 - 属性传输主张，且在报告扩散率值的文献中，15%明确表示长度尺度是单独研磨后测量或根本未提及研磨。扩散率评估合理要求研磨后测量长度尺度。比较了一系列测量方法及由此产生的表观扩散率，描述了每种方法的常见错误和陷阱。以TiNb2O7和Ti2Nb10O29为例，通过严格定量测量分别比较材料扩散率和恒电流性能。溶胶 - 凝胶法制备的样品长度尺度较短、扩散系数较低，但恒电流电池测量显示较短长度尺度能弥补较低扩散率，具有更好的高倍率容量保持率。这表明电池水平指标常与潜在扩散率不同。我们认为材料开发需要重新关注像扩散率这样的属性测量，最佳实践对得出有意义的结构 - 属性关系见解很重要。
英文摘要：
The continuous demand for improved batteries motivates the discovery and advancement of materials with improved transport. Ionic diffusivity is the relevant material property where its measurement depends on accurate assessment of the active material length-scale, generally from the mass-specific surface area. In this perspective, we argue for renewed focus on diffusivity comparisons. A procedural review of 303 recent open-access publications about battery material development revealed two aspects: (1) 49% of publications support structure-property transport claims using diffusivity values and (2) of those reporting diffusivity values, 15% clearly stated that the length scale was measured after grinding-alone or stated that grinding was not used at all. Diffusivity assessment rationally requires length scale measurement after grinding (grind-measure), rather than the reverse. A range of measurement methods are compared, including SEM, BET, and SAXS as well as the resulting apparent diffusivities. Common errors and pitfalls of each of these approaches are described. As an example, datasets are presented for TiNb2O7 (TNO1) and Ti2Nb10O29 (TNO2) made from sol-gel (SOL) and solid state (SS) techniques using rigorous quantitative measurements to separately compare material diffusivities and galvanostatic performance. Here, the SOL samples had shorter length-scales and lower diffusion coefficients. Galvanostatic cell measurements, however, revealed that the shorter length-scales more than compensated for the lower diffusivities with better overall high-rate capacity retention. This example shows how cell level metrics often differ from underlying diffusivities. We argue that materials development needs renewed focus on property measurements like diffusivity where best-practices are important to derive meaningful insights towards structure-property relationships.
