Ultra-fast charging in aluminum-ion batteries: electric double layers on active anode

Xuejing Shen,Zhanjun Wu,Lei Yang,Tao Sun,Alexey Krasnoslobodtsev,Li Tan,Michael Sealy,Renat Sabirianov,Wai-Ning Mei

doi:10.1038/s41467-021-21108-4

Abstract

With the rapid iteration of portable electronics and electric vehicles, developing high-capacity batteries with ultra-fast charging capability has become a holy grail. Here we report rechargeable aluminum-ion batteries capable of reaching a high specific capacity of 200 mAh g−1. When liquid metal is further used to lower the energy barrier from the anode, fastest charging rate of 104 C (duration of 0.35 s to reach a full capacity) and 500% more specific capacity under high-rate conditions are achieved. Phase boundaries from the active anode are believed to encourage a high-flux charge transfer through the electric double layers. As a result, cationic layers inside the electric double layers responded with a swift change in molecular conformation, but anionic layers adopted a polymer-like configuration to facilitate the change in composition.

Highlights

With the rapid iteration of portable electronics and electric vehicles, developing high-capacity batteries with ultra-fast charging capability has become a holy grail
Physics considerations suggest that faster charging requires a larger current injection; but a larger current will result in larger drop in resistance at the interface
If the limitation in charge transfer is removed, we can expect much bigger impacts than mere savings in time. This will eliminate the clear boundary between a supercapacitor and a battery, making the device both high capacity and high rate; and it will provide a deeper understanding of the electric double layers (EDLs)

Summary

Introduction

With the rapid iteration of portable electronics and electric vehicles, developing high-capacity batteries with ultra-fast charging capability has become a holy grail. Phase boundaries from the active anode are believed to encourage a high-flux charge transfer through the electric double layers. If the limitation in charge transfer is removed, we can expect much bigger impacts than mere savings in time This will eliminate the clear boundary between a supercapacitor and a battery, making the device both high capacity and high rate; and it will provide a deeper understanding of the electric double layers (EDLs). Current research treats EDLs as stable nanostructures[12] It is currently not clear how EDLs participate in the reduction of negatively charged ions. It is even less known about how to regulate EDLs in order to facilitate a quick reaction at the interface. We show that the byproducts formed during charging/discharging can be used to calibrate and challenge conventional understanding in the bulk

Methods

Results

Conclusion