The demand for electrochemical energy storage technologies is rapidly increasing due to the proliferation of renewable energy sources and the emerging markets of grid- scale battery applications. The properties of batteries and electrochemical energy storage (EES) technologies ideal for most of these applications, yet, faced with resource constraints, the ability of current lithium-ion batteries (LIB) to match this overwhelming demand is uncertain. Sodium-ion batteries (SIB) are a novel class of batteries with similar performance characteristics to LIB. Since they are composed of earth abundant elements, cheaper and utility scale battery modules can be assembled. As a result of the learning curve in LIB technology, a phenomenal progression in material development has been realised in the SIB concept. In this SIB review, various innovative strategies used in material development, as well as the electrochemical properties of possible anode, cathode and electrolyte combinations are unravelled. Attractive performance characteristics are herein evidenced, based on comparative gravimetric and volumetric energy densities to state-of-the-art LIB. Furthermore, opportunities and challenges towards commercialization are herein discussed. Combined with more industrial adaptations, the commercial prospects of SIB look promising and this challenging new technology is set to play a major role in grid-scale EES applications.

Sodium-Ion Battery Materials and Electrochemical Properties Reviewed

Hard carbons for sodium-ion batteries: Structure, analysis, sustainability, and electrochemistry

Owing to their high cost and safety hazards, and the low abundance of Li in natural resources, the future of Li-ion batteries is becoming difficult. To replace Li-ion batteries, aqueous multivalent ion batteries are considered to be a worthwhile choice. In particular, aqueous zinc ion batteries are becoming an attractive option due to the natural abundance and unique properties of zinc. However, as for the Li-ion battery, the Zn-ion battery also has its own inadequacies in terms of cathodes. Finding a suitable cathode material for Zn-ion batteries with adequate structural stability and high capacity is an uphill task for researchers. This review presents the recent developments of various cathode materials in zinc ion batteries and their effectiveness towards the advancement of Zn-ion batteries. Based on the collected literature, various strategies adopted for enhancing the performance of Zn-ion batteries are also briefly discussed in this review. Furthermore, the explicit progress and future perspectives of Zn-ion batteries are also discussed.

A review on recent developments and challenges of cathode materials for rechargeable aqueous Zn-ion batteries

From Charge Storage Mechanism to Performance: A Roadmap toward High Specific Energy Sodium-Ion Batteries through Carbon Anode Optimization

Tuning nitrogen species in three-dimensional porous carbon via phosphorus doping for ultra-fast potassium storage

Insights on the Na+ ion storage mechanism in hard carbon: Discrimination between the porosity, surface functional groups and defects

Hard carbon derived from cellulose as anode for sodium ion batteries: Dependence of electrochemical properties on structure

Last years have shown an explosion of interest about biochars. Until now, the applications targeted have mostly been in the fields of energy or agronomy. But high-added value applications in the field of electrochemistry, such as hard carbon precursor in anodes for sodium ion batteries, become more and more mentioned as promising uses to investigate. The present study aims at evaluating the feasibility of using biochars from various biomass types for this application and drawing links between biomass properties and the resulting hard carbon electrochemical performance. To achieve this goal, hard carbons were obtained by high-temperature slow pyrolysis of four woody and agricultural biomasses. These hard carbons were prepared as anodes, characterized regarding structural and textural properties and finally tested during successive cycles to assess electrode performances and correlate them with biomass composition. Whatever biomass, the hard carbon could be used in cells and thus biomass appears as a promising feedstock for this application. However, there are apparent differences between biomasses concerning coulombic efficiency and to some extent, cycle stability. Hence resinous wood appears to be the most suitable precursor, while wheat straw would be the least one, probably because of its too high surface area or inorganic element content. Based on these observations, hypotheses were suggested about the influence of lignin and hemicelluloses composition as well as of inorganic elements. To our knowledge, this study is pioneering in proposing a systematic study approach to understand the influence of different biomass properties in a hard carbon electrode for sodium-ion batteries.

Biochars from various biomass types as precursors for hard carbon anodes in sodium-ion batteries

We re-examine the charge transfer mechanism in the Chevrel phase Mo6S8 upon Mg intercalation and deintercalation by the mean of X-ray photoemission spectroscopy. We highlighted a two-step reversible charge transfer process involving successively axial sulfurs and Mo6 cluster redox center. In parallel, the Mg 2p and Mg KLL Auger transition evolution evidenced two insertion sites having different polarizations in accordance with previous studies. The nonconventional metal transition redox reaction, involved during Mg intercalation in Chevrel phase, might be at the origin of its excellent reversibility and intercalation kinetics.

Charge Transfer Mechanism into the Chevrel Phase Mo6S8 during Mg Intercalation

Identification and Quantification of the Main Electrolyte Decomposition By-product in Na-Ion Batteries through FEC: Towards an Improvement of Safety and Lifetime

Sebastien Martinet

Papers

Insights on the Na+ ion storage mechanism in hard carbon: Discrimination between the porosity, surface functional groups and defects

Hard carbon derived from cellulose as anode for sodium ion batteries: Dependence of electrochemical properties on structure

Biochars from various biomass types as precursors for hard carbon anodes in sodium-ion batteries

Charge Transfer Mechanism into the Chevrel Phase Mo6S8 during Mg Intercalation

Identification and Quantification of the Main Electrolyte Decomposition By-product in Na-Ion Batteries through FEC: Towards an Improvement of Safety and Lifetime