Reducing the Charge Carrier Transport Barrier in Functionally Layer‐Graded Electrodes

Abstract

Lithium-ion batteries (LIBs) are primary energy storage devices to power consumer electronics and electric vehicles, but their capacity is dramatically decreased at ultrahigh charging/discharging rates. This mainly originates from a high Li-ion/electron transport barrier within a traditional electrode, resulting in reaction polarization issues. To address this limitation, a functionally layer-graded electrode was designed and fabricated to decrease the charge carrier transport barrier within the electrode. As a proof-of-concept, functionally layer-graded electrodes composing of TiO (B) and reduced graphene oxide (RGO) exhibit a remarkable capacity of 128 mAh g at a high charging/discharging rate of 20 C (6.7 A g ), which is much higher than that of a traditionally homogeneous electrode (74 mAh g ) with the same composition. This is evidenced by the improvement of effective Li ion diffusivity as well as electronic conductivity in the functionally layer-graded electrodes.

Building High Power Density of Sodium-Ion Batteries: Importance of Multidimensional Diffusion Pathways in Cathode Materials

“…The ultimate goal for advanced sodium ion battery devices has never changed, that they should be thoroughly competitive with the lithium ion battery in energy density, power density, and lower overall manufacturing cost (Tang et al, , 2018Zhang et al, 2017Zhang et al, , 2019Guo et al, 2020). For fullcell sodium ion battery devices, the emphasis always falls on the cathode parts, since they possess key parameters such as high enough operation voltages, large theoretical capacity, and most of all, acceptable high-rate capability.…”

A Simple Prelithiation Strategy To Build a High‐Rate and Long‐Life Lithium‐Ion Battery with Improved Low‐Temperature Performance

“…Nowadays, the market of LIBs powered EVs increases steadily. In order to satisfy the high power demand on start/acceleration process and the quick electric refueling, various high‐rate LIBs and related electrode materials have been developed over recent years . During the same time, many efforts have been made to increase the cycle life of LIBs to ensure the service life of EVs .…”

Fast‐Charging and High Volumetric Capacity Anode Based on Co3O4/CuO@TiO2 Composites for Lithium‐Ion Batteries

“…Therefore, many researchers have investigated alternative anodic materials to replace graphite . Among them, TiO 2 has attracted considerable interest as an anodic material for next‐generation LIBs owing to its relatively high lithiation potential (≈1.7 V vs. Li/Li + ), which enables safer operation during fast charging . In addition, TiO 2 undergoes an extremely small volume expansion (≈3 %) during the charge/discharge cycle, leading to good cycling stability and rate capability.…”

“…[9][10][11] Amongt hem,T iO 2 has attracted consider-able interest as an anodic materialf or next-generation LIBs owingt oi ts relatively high lithiation potential ( % 1.7 Vv s. Li/ Li + ), which enables safer operation during fast charging. [12][13][14] In addition, TiO 2 undergoes an extremely small volume expansion ( % 3%)d uring the charge/discharge cycle, leadingt o good cycling stabilitya nd rate capability.I ns piteo ft hese advantageouss tructuralp roperties, their low gravimetric capacity (170 mA h À1 g À1 )a nd low electronic and ionic transportk inetics continued to remain ag reat challenge. [15][16][17] Thus, variouss trategies to improve the overall electrochemical properties have been reported; for example, introducing foreigna ctivem aterials into TiO 2 using coating or ion-doping methods.…”