This review introduces current research on materials and proposes future directions for sodium-ion batteries.

Lithium–sulfur (Li–S) batteries have recently attracted enormous attention in the energy-storage sector owing to their high theoretical capacities (1675 mA h g⁻¹), high theoretical energy densities (2600 W h kg⁻¹), and cost-effectiveness compared to the state-of-the-art Li-ion batteries. Despite these merits, the practical application of Li–S battery technology is hindered by certain severe drawbacks. Therefore, current challenges need to be diagnosed in order to find effective solutions to these Li–S battery-commercialization obstacles. To help direct future work, we not only summarize current research trends, but also highlight an effective solution for the practical applications of Li–S batteries. In this review, we thoroughly summarize current research work on three kinds of Li–S battery systems based on different cathode materials, namely sulfur (S₈), lithium sulfide, and sulfurized-polyacrylonitrile. In addition, we also provide insight into the current challenges associated with Li–metal anodes in Li–S batteries. We then summarize and discuss an effective solution to these issues, namely the use of Li–metal-free anodes or all-solid state electrolytes in Li–S full cell systems.

P3-K_0.69CrO₂ cathode is successfully synthesized via an electrochemical ion-exchange route and delivers excellent cycling stability and power capability in K-ion batteries.

Nano-scale Al₂O₃ coating was effective at resolving the degradation pathways of the cathode surface in sodium-ion batteries.

Simultaneous surface MgO coating to bulk Mg doping of Na[Ni_0.5Mn_0.5]O₂ cathode produces great synergy in sodium-ion battery performances.