Prospective Cathode Materials for All-Solid-State Batteries

Abstract

AbstractThe adoption of solid electrolytes in rechargeable batteries has bestowed the energy storage devices with advantages such as high energy density, improved life span and most importantly improved safety. Changing from the flammable liquid organic electrolytes to the non-flammable solid inorganic and polymeric electrolytes brings about a drastic change to the overall set-up of the battery pack, allowing for the fabrication of compact batteries suitable for application in small electronic devices and wearable technologies. However, the electrolyte phase change also brings about changes in the electrolyte–electrode dynamics which impact the overall performance of the battery. Therefore, an advancement of the electrolyte with regard to safety and performance issues should be accompanied by an analogous development of electrode materials that will be complementary to the optimized operation of the electrolyte. Hence in this chapter we discuss the prospective electrode material that can be applied in cathode active material (CAM) in all-solid-state batteries (ASSBs). We take a special look at the CAMs that have been developed for use in all-solid-state lithium-ion batteries (ASSLIBs) and to a lesser extent the lithium metal batteries (ASSLBs) as lithium technology batteries have dominated the commercial application of rechargeable batteries. Particular attention is given to materials such as the lithiated transition metal compounds that are comprised of layered and spinel oxides (LixMyOz, M = Mn, Co, Ni, etc.), and the three-dimensional polyanionic compounds (LixMyXOz, X = P, S, Si, Mo, W, etc.) and fluorinated polyanionic compounds (LixMyXOzF). Detailed discussions are given of the structural identities of such materials and the different preparation techniques/methods that have been used so far to synthesize materials of different sizes and morphologies, and how these aspects affect the electrochemical performance of the electrode material. We also give some examples of reported literature that employed the discussed cathode active materials in ASSLIBs and ASSLBs, as well as how drawbacks associated with these materials have been dealt with in order to exploit the full functionality of the electrode materials.KeywordsSolid-state batteryLithium-ion batteryCathode materialTransition metal compoundsCapacity