Positron Annihilation Spectroscopy as a Diagnostic Tool for the Study of LiCoO2 Cathode of Lithium-Ion Batteries

Gioele Pagot,Bernardo Barbiellini,Valerio Toso,Vito Di Noto,Rafael Ferragut

doi:10.3390/condmat6030028

Abstract

Positron annihilation spectroscopy using lifetime and Doppler broadening allows the characterization of the lithiation state in LiCoO2 thin film used in cathode of lithium-ion batteries. The lifetime results reflect positron spillover because of the presence of graphite in between the oxide grains in real cathode Li-ion batteries. This spillover produces an effect in the measured positron parameters which are sensitive to delocalized electrons from lithium atoms as in Compton scattering results. The first component of the positron lifetime corresponds to a bulk-like state and can be used to characterize the state of charge of the cathode while the second component represents a surface state at the grain-graphite interface.

Highlights

Li-ion batteries are dominating the market of energy storage devices in the portable electronic and electric vehicle fields [1]
A fundamental understanding of the processes occurring during the operation of the battery, with particular attention at the changes resulting from the Li+ insertion and extraction reactions is required in order to assist the designing of the materials
The identification of suitable signals to be monitored during the battery cycling is needed in order to analyze and predict the state of health (SOH) and state of charge (SOC) of the device

Summary

Introduction

Li-ion batteries are dominating the market of energy storage devices in the portable electronic and electric vehicle fields [1]. The development of novel and high-performing materials in this technology is an urgent need In this regard, the research is primarily focused on: (i) the transition from the costly and capacity limited graphite anode towards silicon and lithium metal [2,3,4,5,6], (ii) the designing of solid-state ceramic and polymer electrolytes endowed with a wide electrochemical stability window and stable towards the. Li-metal anode [7,8,9,10,11,12,13,14,15,16], and (iii) the development of high-voltage and high-energy cathode materials [17,18,19,20,21,22,23] This latter component (i.e., the cathode) typically limits the energy density of the resulting full cell, becoming one of the most important materials to focus attention on. The identification of suitable signals to be monitored during the battery cycling is needed in order to analyze and predict the state of health (SOH) and state of charge (SOC) of the device

Methods

Results

Conclusion