Asymmetric Temperature Modulation for Extreme Fast Charging of Lithium-Ion Batteries

Unveiling Capacity Degradation Mechanism of Li‐ion Battery in Fast‐charging Process

“…The above results reveal that limiting the cell's operation to a relatively low SOC (i. e., a relatively low charging cutoff voltage) can effectively alleviate capacity degradation of the Li‐ion batteries in the fast‐charging applications. This strategy has been well confirmed by a recent work, showing that exceptional fast‐charging stability of Li‐ion pouch cells could be obtained by limiting the SOC to 80 % although its original claim was an asymmetric temperature modulation that enables the cell to rapidly raise the temperature for effective charging.…”

Rapid Lithium Diffusion in Order@Disorder Pathways for Fast‐Charging Graphite Anodes

“…[4,5] Tremendous strategies have been devoted to improve the charging capability of graphite anodes at high rates. [4,[6][7][8] Regulating Li þ solvation structure, [8] introducing an artificial coating layer on graphite surface, [6,9] modifying graphite bulk materials, [6,10] and optimizing charging protocols [2] are strongly considered recently. Particularly, precoating the surface of graphite particles with thin polymers, [11] inorganic compounds, [6,9,12,13] and hybrid organic/inorganic layers is explored, [14] which can effectively inhibit the decomposition of electrolyte, increase initial Coulombic efficiency, and reduce irreversible capacity loss.…”

Challenges and Strategies for Fast Charge of Li‐Ion Batteries

“…All Li observed in the post‐mortem analyses are either isolated (dead) Li or those in the regions where the electrolyte is completely depleted. The results obtained from non‐destructive methods, such as those by analyzing the change in voltage or differential voltage during post‐charging relaxation, and those by observing the change in capacity or differential capacity in the subsequent discharge, are changed with rest time due to the issue that the plated Li chemically re‐intercalates into graphite.…”

“…As shown in Figure c, the activation energy of the 1/R ct is inherently large compared with those of the 1/R b and 1/R sl , suggesting that the polarization resulting from R ct can be dramatically reduced by raising the temperature. As such, Yang et al proposed charging the battery at ∼60 °C and discharging at ambient temperature, finding that a high energy pouch cell (209 Wh kg −1 , Gr/NMC532) could retain 91.7 % of capacity after 2,500 cycles at a 10 min charging rate. In addition, chemical heteroatom doping and physical hybridizing with other anode materials that have higher lithiation potentials or better rate capability compared with the pristine graphite, such as hard carbon, amorphous Si, and SiO, are shown to some extent to alleviate Li plating.…”

“…Therefore, the SOC is a better parameter than voltage to be used for terminating the charging process. For example, Zhang found that the capacity retention of Gr/NCA cells in 10 C CCCV‐charging cycling can be dramatically stabilized by lowering the charging cutoff voltage to 4.0 V from the normal 4.2 V. Similarly, Yang et al demonstrated that high energy Gr/NMC532 pouch cells (9.5 Ah, 170 Wh kg −1 ) can retain 91.7 % of the original capacity after 2,500 cycles at a 10‐min charging rate by limiting the capacity to 80 % SOC and charging the battery at ∼60 °C. The above facts reveal that both the large internal resistance at low SOCs and the chemical and structural instability of the layered cathode materials at high SOCs should be taken into account for an ideal fast‐charging protocol.…”