Microsized alloying anodes are the next practical step in achieving advanced batteries with higher energy density, yet the major challenge, associated with their alloying processing, lies in electro-mechanical failure phenomena caused by stress concentration. Here, we develop a universal grain boundaries (GBs) strategy on microsized alloying anodes for sodium ion batteries. The densified GBs function as fast diffusion paths to promote more homogenous sodiation. They facilitate consistent sodiation kinetics by stress transportation and delocalization, leading to electrochemical attributes superior to reported nanosized anodes (microsized Bi as a model, 200.5 mAh/g@277.5C, 1043.1 mAh/cm³@40C, high tap density of ∼2.4 g/cm³). Furthermore, GBs also act as dislocation catchers and barriers, significantly altering the sodiation behavior and subsequent structural evolution, and giving rise to enhanced fracture resistance and cycling stability. This work provides the key insight into GB-associated effects in microsized anodes on electro-mechanical coupling process, essential for development of advanced batteries.

中文翻译：

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在微米合金颗粒中致密化晶界实现应力离域，以实现高级钠储存


微型合金化阳极是实现具有更高能量密度的先进电池的下一个实际步骤，但与其合金化加工相关的主要挑战在于应力集中引起的机电故障现象。在这里，我们在钠离子电池的微型合金负极上开发了一种通用晶界 （GBS） 策略。致密化的 GB 起到快速扩散路径的作用，以促进更均匀的钠化。它们通过应力传递和离域促进一致的钠化动力学，从而产生优于已报道的纳米级阳极（微型 Bi 模型，200.5 mAh/g@277.5C，1043.1 mAh/cm³@40C，∼2.4 g/cm³ 的高振实密度）的电化学特性。此外，GB 还充当位错捕捉器和屏障，显着改变钠化行为和随后的结构演变，并增强抗断裂性和循环稳定性。这项工作为微型负极中 GB 相关对机电耦合过程的影响提供了关键见解，这对于先进电池的开发至关重要。