Designing Novel Sulphate-based Ceramic Materials as Insertion Host Compounds for Secondary Batteries

Abstract

Rechargeable batteries have propelled the wireless revolution and automobiles market over the past 25 years. Developing better batteries with improved energy density demands unveiling of new cathode ceramic materials with suitable diffusion channels and open framework structure. In this pursuit of achieving higher energy density, one approach is to realize enhanced redox voltage of insertion of ceramic compounds. This can be accomplished by incorporating highly electronegative anions in the cathode ceramics. Building on this idea, recently various sulphate- based compounds have been reported as high voltage cathode materials. The current article highlights the use of sulphate (SO₄) based cathodes to realize the highest ever Fe³⁺/Fe²⁺ redox potentials in Li-ion batteries (LiFeSO₄F fluorosulphate: 3.9 V vs Li/Li⁺) and Na-ion batteries (Na₂Fe₂(SO₄)₃ polysulphate: 3.8 V vs Na/Na⁺). These sulphate-based cathode ceramic compounds pave way for newer avenues to design better batteries for future applications.

Keywords:

• Energy storage
• Li-ion batteries
• Na-ion batteries
• Cathode ceramic
• High voltage
• Fluorosulphates
• Triplite
• Polysulphates
• Alluaudite