Leveraging Titanium to Enable Silicon Anodes in Lithium‐Ion Batteries

Abstract

Silicon is a promising anode material for lithium‐ion batteries because of its high gravimetric/volumetric capacities and low lithiation/delithiation voltages. However, it suffers from poor cycling stability due to drastic volume expansion (>300%) when it alloys with lithium, leading to structural disintegration upon lithium removal. Here, it is demonstrated that titanium atoms inside the silicon matrix can act as an atomic binding agent to hold the silicon atoms together during lithiation and mend the structure after delithiation. Direct evidence from in situ dilatometry of cosputtered silicon–titanium thin films reveals significantly smaller electrode thickness change during lithiation, compared to a pure silicon thin film. In addition, the thickness change is fully reversible with lithium extraction, and ex situ post‐mortem microscopy shows that film cracking is suppressed. Furthermore, Raman spectroscopy measurements indicate that the Si–Ti interaction remains intact after cycling. Optimized Si–Ti thin films can deliver a stable capacity of 1000 mAh g−1 at a current of 2000 mA g−1 for more than 300 cycles, demonstrating the effectiveness of titanium in stabilizing the material structure. A full cell with a Si–Ti anode and LiFePO4 cathode is demonstrated, which further validates the readiness of the technology.

Engineering Nanostructured Silicon and its Practical Applications in Lithium‐Ion Batteries: A Critical Review

“…[97] However, capacity fades rapidly owing to material pulverization caused by the large volume changes. Inactive metals, like Cu, [98] Ag, [99] Ti, [11] Ge, [100] and Fe, [9,101] mainly play the role in conducting electrons and providing a mechanical support to alleviate the volume expansion. Although the incorporation of additional metal elements leads to better cycling performance, an in-depth understanding of how metals interact with Si during cycling is still lacking.…”

“…[10] In addition, introducing a metallic phase could also buffer the volume change and render the composites more reversible. [11] A second element either forming composites, compounds, or alloys could alleviate the stress caused by volume change. A typical example, SiO x , shows the reversible capacity as high as 1200-1400 mAh g À1 .…”

Critical Review of the Use of Reference Electrodes in Li-Ion Batteries: A Diagnostic Perspective

“…Larger electrochemical cells, such as cylindrical, prismatic, and pouch cells, where the electrodes are usually double-side coated and rolled or folded, are produced as two-electrode cells and are mostly used for practical applications (Figure 12) [108]. Specific lab-scale cells, designed to improve, for example, the reproducibility of EIS measurements [109] or to perform operando studies of electrode expansion during cycling [110], have been implemented in recent years by commercial companies [111]. Larger electrochemical cells, such as cylindrical, prismatic, and pouch cells, where the electrodes are usually double-side coated and rolled or folded, are produced as two-electrode cells and are mostly used for practical applications (Figure 12) [108].…”

“…Larger electrochemical cells, such as cylindrical, prismatic, and pouch cells, where the electrodes are usually double-side coated and rolled or folded, are produced as two-electrode cells and are mostly used for practical applications (Figure 12) [108]. Specific lab-scale cells, designed to improve, for example, the reproducibility of EIS measurements [109] or to perform operando studies of electrode expansion during cycling [110], have been implemented in recent years by commercial companies [111]. Various research works have described modification of cells by adding an internal RE [24,35,37,38,64,73,78,95,99] and optimization of the RE location within the cell to avoid measurement artefacts [61,62,76,78,96,99,[112][113][114][115].…”

Synergic effects of the decoration of nickel oxide nanoparticles on silicon for enhanced electrochemical performance in LIBs

“…The hybridization of silicon with different materials having particular properties for LIBs could be an efficient approach to easing the abovementioned problems. [18][19][20][21][22][23][24] Researchers are focusing on different structural design approaches for the enhancement of the Li-ion storage capabilities of silicon.…”