Twin boundary defect engineering improves lithium-ion diffusion for fast-charging spinel cathode materials

Abstract

Defect engineering on electrode materials is considered an effective approach to improve the electrochemical performance of batteries since the presence of a variety of defects with different dimensions may promote ion diffusion and provide extra storage sites. However, manipulating defects and obtaining an in-depth understanding of their role in electrode materials remain challenging. Here, we deliberately introduce a considerable number of twin boundaries into spinel cathodes by adjusting the synthesis conditions. Through high-resolution scanning transmission electron microscopy and neutron diffraction, the detailed structures of the twin boundary defects are clarified, and the formation of twin boundary defects is attributed to agminated lithium atoms occupying the Mn sites around the twin boundary. In combination with electrochemical experiments and first-principles calculations, we demonstrate that the presence of twin boundaries in the spinel cathode enables fast lithium-ion diffusion, leading to excellent fast charging performance, namely, 75% and 58% capacity retention at 5 C and 10 C, respectively. These findings demonstrate a simple and effective approach for fabricating fast-charging cathodes through the use of defect engineering.

Deformation Mechanisms of FCC-Structured Metallic Nanocrystal with Incoherent Twin Boundary

“…Previous studies have indicated that ITB migration can also occur through the movement of this 9R structure [58]. While SFs serving as dislocation sources have rarely been reported in experiments, several important studies have also shown that TBs can significantly affect the physical and chemical properties of materials [60,61]. Thus, our results may also provide clues for understanding how and why the physical and chemical properties of materials usually change with different structures and boundaries [62,63], especially during deformation and practical application.…”

Entropy and crystal-facet modulation of P2-type layered cathodes for long-lasting sodium-based batteries

“…At the high voltage region (4.0–4.3 V), the Nyquist plots of both samples exhibit two distinct parts including a depressed semicircle in the high-frequency region and an inclined line in the low-frequency zone. The high-frequency semicircle should be related to the charge-transfer resistance 39 – 41 . By comparing the diameters of the semicircles in the high-voltage region (Supplementary Table 9 ), the impedances of CuMgTi-571 and NaMNO 2 are similar, implying similar electronic conductivity of the two de-sodiated samples.…”

Defect engineering of electrode materials towards superior reaction kinetics for high-performance supercapacitors

“…For instance, Wang and coworkers prepared LiMn 2 O 4 with plenty of twin boundaries (LMO-TB) by varying the addition of lithium salt to understand the relationship between electrochemical properties and defects. 102 As illustrated in Fig. 3f and g, two types of twin boundaries (symmetrical and asymmetrical twinning) could be obviously observed in atomically resolved high-angle annular dark-field scanning transmission electron microscopy (HAADF STEM) images.…”