Incorporating α-Al₂O₃ Nanodots into Expanded Graphite Anodes toward Stable Fast Charging for Lithium-Ion Batteries

Abstract

High-power lithium-ion batteries place high demands on the fast charging ability of electrode materials, while for the current graphite anode, it suffers from anisotropic and sluggish Li+ transport due to its small interlayer spacing. In addition, the large polarization at low lithiation potential at a high rate leads to Li+ deposition and side reactions of Li with the electrolyte. In this work, α-Al2O3 nanodots incorporated into aggregates of thin-layer graphite have been developed by facile high-energy ball milling of graphite and layer-structured pseudo-boehmite. By optimization, the ball-milled graphite/Al2O3 (BG/Al2O3) manifests a high reversible capacity of 344 mAh g–1 higher than the 98.7 mAh g–1 of graphite after 500 cycles at 1 A g–1 (∼2.7C) and 200 mAh g–1 higher than the 59.6 mAh g–1 of raw graphite at 3 A g–1 after 500 cycles. The wrinkled edges and expanded interlayer spacing generated by high-energy ball milling optimize the Li+ transport and accelerate reaction kinetics, contributing high pseudocapacitance and enabling fast charging ability. The α-Al2O3 nanodots can decrease the side reactions between the electrolyte and graphite electrode, contributing high cyclic stability. This study lays a foundation for the one-step mechanical force chemistry method to prepare highly stable fast-charging graphite anode materials for lithium-ion batteries.

Expanded graphite incorporated with Li4Ti5O12 nanoparticles as a high-rate lithium-ion battery anode

“…11 Various strategies have been researched, including chemical oxidation, surface coating treatment, and porous-structure design. [12][13][14][15][16][17][18][19] By coating an arti-cial Li + conductor on the graphite surface, the interface Li + diffusion resistance could be obviously decreased, resulting in an enhanced kinetic character. 20 Lee et al applied Li 4 Ti 5 O 12 (LTO) as a coating layer for MCMB (middle phase carbon microsphere) surface modication, achieving smaller interface resistance than that of the original MCMB aer 40 cycles, due to the LTO layer inhibiting the successive decomposition of electrolyte at the electrode/electrolyte interface during long cycles.…”

“…The results showed that the reversible capacities of GLG at 1, 5 and 10C were about 220, 150 and 100 mA h g −1 , respectively, which were much higher than those of the original graphite. Ma et al 13 synthesized graphite/Al 2 O 3 composites via facile high-energy ball milling. The ball milling treatment not only introduced porous structures for Li + adsorption but also expanded the layer spacing for fast Li + diffusion in the bulk.…”

Improving Natural Microcrystalline Graphite Performances by a Dual Modification Strategy toward Practical Application of Lithium Ion Batteries

“…In view of the abovementioned problems, a large number of research works have been carrying out. At present, common modification methods mainly include mild expansion of oxidation, − metal or metal oxide deposition, − carbon coating, , and doping with other noncarbon elements. Among them, mild expansion of oxidation is a relatively simple and low-cost technology route to modify MG.…”

Low-temperature tolerant lithium-rich manganese-based cathode enabled by facile SnO2 decoration

“…S8 †), suggesting the superior pseudocapacitive lithium storage of S-LLOs, in comparison to LLOs. 77 Both the enhanced diffusion kinetic coefficient and superior pseudocapacitive lithium storage facilitate the electrochemical performance of S-LLOs cathode material.…”