Mojtaba Mirzaeian, ... Rizwan Raza, in Reference Module in Materials Science and Materials Engineering, 2021
Lithium-ion batteries (LIBs) are considered the pioneering technology that has been successfully adopted as a power source for wide range of applications including portable electronics and electric/hybrid electric vehicles (EVs/HEVs) after their commercialization by Sony Corporation in 1991 (Perveen et al., 2020; Duan et al., 2020; Tian et al., 2020). Despite their commercial success in numerous applications, LIBs have not been deployed in large-scale electrical energy storage (EES) applications due to elevated cost and limited supply of lithium resources over the coming years as shown in Fig. 1, restricting their wider use. Total reserves of lithium are estimated between 15–30 Mt (million tons) with uneven geographical distribution whereas, recycling rate of Li from spent LIBs is only around 1% which can be considered as more or less non-existent (Vikström et al., 2013; Speirs et al., 2014). This scenario requires immediate effort to find substitute material to replace lithium-ion battery systems based on more cost-effective and easily sourced materials.
Sodium-ion batteries (SIBs) have emerged as suitable alternative owing to their similar physiochemical/electrochemical properties and essentially inexhaustible/low cost elemental sodium (comparison between relative reserve of elemental lithium and sodium in earth crust is shown in Fig. 2) making SIBs a promising candidate to meet future energy storage requirements particularly large scale EES applications. Key benefit of using Na+ is the economy of scale since Na+ is the fifth most abundant element in earth crust as shown in Fig. 2. Furthermore, cast can be reduced even further by using low cost aluminum (Al) as a current collector since it does not form alloy with Na+ based anode and cathode.
Despite these advantageous characteristics, SIBs struggle to compete with LIBs due to their inferior storage capacity, sluggish reaction kinetics and poor rate capability especially when used in conjunction with graphitic carbon, which is the most frequently, used anode material. This is due to the larger ionic radius of 1.02 Å of Na+ compared to ionic radius of 0.76 Å for Li+ making Li-ion intercalation more effortlessly attainable. Up until late 80 s, SIBs were successful in attaining similar research attention as LIBs however, the discovery of more cost-effective, high capacity and electrochemically active anode material based on graphite resulted in abandonment of SIBs altogether (Yabuuchi et al., 2014). Despite this neglection, research activity has recently witnessed reacceleration of research on sodium ion batteries after successful insertion of Na+ ion in hard carbon where high storage capacity of around 300 mAh g−1 was achieved which is similar to that of LIBs using graphite as anode (Stevens and Dahn, 2000).
From earlier discussion, it can be appreciated that SIBs are not considered as direct competitor of LIBs especially in area of volumetric or gravimetric energy densities, but they will rather complement Li-ion battery systems in large-scale application due to their competitive pricing, ultimately resulting in the price stabilization of lithium-based batteries. Therefore, success of SIBs will be governed by further research activity and investment in commercialization of the technology in order to close the technological gap between these two state of the art battery systems. In this brief article, comparison between lithium and sodium based rechargeable batteries will be made, followed by detail discussion on various anode, cathode and electrolyte materials and their effect on performance of SIBs.