Dual Storage Mechanism Induced High Capacity Cathode for Rechargeable Aluminium Ion Battery

Abstract

Rechargeable energy storage devices have attained much interest in the society as it provides solution to energy crisis. The excessive use of lithium due to ever increasing demand of lithium ion battery in stationary energy storage and portable electronic devices coupled with restricted availability, urges to move towards alternative low cost energy storage device. Developing a new type of sustainable electrochemical energy storage device depends on the exploration of electrochemistry of other alkali metals. Looking for the low cost energy storage device, Al is the third most abundant element in the Earth’s crust and can be used as low cost energy storage device. Moreover, it can exchange three redox electrons per cations so that the energy density of the battery is high compared to lithium based storage system. But the lack of suitable cathode material is the major draw back of aluminium ion battery not reaching the level of commercialization. Carbon based materials like graphite and reduced graphene oxide have been probed as a cathode material where the charge storage occurs by the in intercalation of AlCl4 - anion into the graphite interlayer which limits the specific capacity in the range of 80 to 100 mAh g-1. Cathode materials, which can also intercalate trivalent aluminium ions, can enhance the specific capacity. This work aims to design a cathode material, which can react with both Al3+ and AlCl4 – ions. Sulfur, a cost effective material, embedded in distorted multiwalled carbon nanotubes (DCNT) provides a new concept of both intercalation of AlCl4 – ions in DCNT as well as conversion reaction of sulfur with trivalent aluminium ions. This design of cathode delivers a specific capacity of 500 mAh g-1 at a current density of 50 mA g-1 with a stable cycling of about 600 cycles and can lead to the development of high energy density rechargeable aluminium ion battery.