Uniform Lithium Deposition Achieved by SnO₂/Hydroxypropyl Methyl Cellulose Composite Separator toward Ultrastable Lithium Metal Batteries

Abstract

The uncontrollable growth of lithium (Li) dendrites impedes the development of practical applications for the long-awaited lithium metal batteries. In this work, a strategy is proposed to protect the Li anode with a composite separator of in situ formed SnO2 and hydroxypropyl methyl cellulose (HPMC) on the polyethylene (PE) substrate. Based on the use of SnO2/HPMC@PE separator, the Li||Li cell has an ultralong cycle life of more than 2000 h and ultralow-voltage hysteresis of 11.1 mV, whereas the cell with PE separator only has the cycle life of 800 h and the voltage hysteresis of up to 222.9 mV. Moreover, Li||LiNi0.6Co0.2Mn0.2O2 (NCM622) has an initial discharge capacity of 142.3 mAh g–1 and a capacity retention of 77.9% after 250 cycles at 1 C, which are higher than those of PE (140.6 mAh g–1 with retention of 59.5%). All of the enhanced performance can be ascribed to a regulable SEI film that can be formed on the Li foil in direct contact with the SnO2 layer, which decreases the Li nucleation overpotential and facilitates ultimately uniform Li deposition. This work demonstrates the feasibility of using a modified separator to achieve stable Li metal batteries.

ZnO@C Coated Cellulose‐Based Separators Control Lithium Deposition Direction to Stable Lithium Metal Batteries

“…We were able to conclude that ZnO@C/cellulose plays an effective role. A comparison of the long cycle of Li||Li symmetric cells with the previous worth of literature in the separator area is shown in Figure 3c, [ 16,33–48 ] confirming the possibility of our work to optimize performance in LMBs. We additionally examined at the Li||Cu half cells with PP, cellulose, and ZnO@C/cellulose separators to illustrate Li deposition behavior.…”

A Multifunctional Molecular Bridging Layer for High Efficiency, Hysteresis‐Free, and Stable Perovskite Solar Cells

“…Additionally, the Li + ions accumulated in the interface and bulk of SnO 2 due to its high Li + affinity [ 44 ] and K + in the SnO 2 diffusion into the Spiro‐OMeTAD layer provides intracellular ion equilibration. [ 23 ] For the original device, the concentration of Li + ions in the SnO 2 layer is unchanged concerning the device with 50 times forward and reverse scans.…”

Eco-Friendly Lithium Separators: A Frontier Exploration of Cellulose-Based Materials

“…This is because on the one hand, inorganic particles can be used to improve the flame retardancy and electrode interface compatibility of cellulose separators, and on the other hand, organic coatings can be used to improve the electrolyte wettability of cellulose separators [175,176]. Su and coworkers [177] prepared battery separators on a polyethylene (PE) substrate with SnO2 and hydroxypropyl methyl cellulose (HPMC), which had an initial discharge capacity of 142.3 mAh g −1 and a capacity retention of 77.9% after 250 cycles at 1C, which was higher than that of PE (140.6 mAh g −1 and 59.5% retention). The film can be formed on the Li foil in direct contact with the SnO2 layer, which reduces the Li nucleation overpotential and promotes eventual uniform Li deposition.…”