Dense T-Nb2O5/Carbon Microspheres for Ultrafast-(Dis)charge and High-Loading Lithium-Ion Batteries

Amorphous Anode Materials for Fast-charging Lithium-ion Batteries

Fast-charging technology is set to revolutionize the field of lithium-ion batteries (LIBs), driving the creation of next-generation devices with the ability to get charged within a short span of time. From the anode perspective, it is of paramount importance to design materials that can withstand continuous Li+ insertion/deinsertion at high charging rates and still remain unaffected by factors such as mechanical fractures, electrolyte side reactions, polarisation, lithium plating and heat generation. Herein, the recent advancements in the design of amorphous materials as anodes for fast-charging LIBs have been discussed. While the development of this particular class of materials for application in high-rate anodes has been paid limited attention in recent literature, it holds immense promise for improving the fast-charging capabilities. This concept summarizes the recent strides made in this emerging field, outlining the strategies employed in the design of amorphous anodes and emphasizing the crucial role played by the amorphous nature in achieving fast-charging performance. Further, the successive initiatives that can be undertaken to drive the progress of amorphous materials for fast charging LIBs have also been detailed, which could potentially improve their commercial viability.

Insight into the Li-Storage Property of Surface-Modified Ti2Nb10O29 Anode Material for High-Rate Application

Ti-based anode materials are considered to be an alternative to graphite anodes to accomplish high-rate application requirements. Ti2Nb10O29 (TNO15) has attracted much attention due to its high lithium storage capacity through the utilization of multiple redox couples and a suitable operating voltage window of 1.0 to 2.0 V vs Li/Li+. However, poor intrinsic electronic conductivity has limited the futuristic applicability of this material to the battery anode. In this work, we report the modification of TNO15 by introducing oxygen vacancies and using few-layered carbon and copper coatings on the surface to improve its Li+ storage property. With the support of the galvanostatic intermittent titration technique (GITT), we found that the diffusion coefficient of carbon/copper coated TNO15 is 2 orders of magnitude higher than that of the uncoated sample. Here, highly conductive copper metal on the surface of the carbon-coated oxygen-vacancy-incorporated TNO15 increases the overall electronic and ionic conductivity. The prepared TNO15-800-C-Cu-700 half-cell shows a significant rate capability of 92% when there is a 10-fold increase in the current density. In addition, the interconnected TNO15 nanoparticles create a porous microsphere structure, which enables better Li-ion transportation during charge/discharge process, and experiences an enhancement after the carbon and copper coating on the surface of the primary TNO15 nanocrystallites.

Design of Cathode Coating Using Niobate and Phosphate Hybrid Material for Sulfide-Based Solid-State Battery

Coating the surface of the cathode active material of all-solid-state batteries with sulfide-based solid electrolytes is key for improving and enhancing the battery performance. Although lithium niobate (LiNbO₃) is one of the most representative coating materials, its low durability at a highly charged potential and high temperature is an impediment to the realization of high-performance all-solid-state batteries. In this study, we developed new hybrid coating materials consisting of lithium niobate (Li-Nb-O) and lithium phosphate (Li-P-O) and investigated the influence of the ratio of P/(Nb + P) on the durability performance. The cathode half-cells, using a sulfide-based solid electrolyte Li₆PS₅Cl/cathode active material, LiNi_0.5Co_0.2Mn_0.3O₂, coated with the new hybrid coating materials of LiP_xNb_1-xO₃ (x = 0-1), were exposed to harsh conditions (60 °C and 4.55 V vs Li/Li⁺) for 120 h as a degradation test. P substitution resulted in higher durability and lower interfacial resistance. In particular, the hybrid coating with x = 0.5 performed better, in terms of capacity retention and interfacial resistance, than those with other compositions of niobate and phosphate. The coated cathode active materials were analyzed using various analytical techniques such as scanning electron microscopy/energy-dispersive X-ray spectroscopy, transmission electron microscopy (TEM), X-ray photoelectron spectroscopy, and X-ray absorption spectroscopy (XAS) to elucidate the improvement mechanism. Moreover, the degraded cathodes were observed using time-of-flight secondary-ion mass spectrometry, TEM/electron diffraction, and XAS. These analyses revealed that the Nb-O-P coordination in the hybrid coating material captured O by P. The coordination suppressed the release of O from the coating layer as a decomposition side reaction to realize a higher durability than that of LiNbO₃.