As the market for electric vehicles and portable electronic devices continues to grow rapidly, sodium-ion batteries (SIBs) have emerged as energy storage systems to replace lithium-ion batteries (LIBs). However, sodium-ion is heavier and larger than lithium-ion, resulting in volume expansion and slower ion transfer. It is necessary to find suitable anode materials with high capacity and stability. In addition, wearable electronics are starting to be commercialized, requiring a binder-free electrode used in flexible batteries. In this work, we synthesized nano flake-like VSe₂ using organic precursor and combined it with MWCNT as carbonaceous material. VSe₂@MWCNT was mixed homogenously using sonication and fabricated film electrodes without a binder and substrate via vacuum filter. The hybrid electrode exhibited high-rate capability and stable cycling performance with a discharge capacity of 469.1 mAhg⁻¹ after 200 cycles. Furthermore, VSe₂@MWCNT exhibited coulombic efficiency of ~99.7%, indicating good cycle stability. Additionally, VSe₂@MWCNT showed a predominant 85.5% of capacitive contribution at a scan rate of 1 mVs⁻¹ in sodiation/desodiation process. These results showed that VSe₂@MWCNT is a suitable anode material for flexible SIBs.

Sodium ion batteries (SIBs) have drawn interest as a lithium ion battery (LIB) alternative owing to their low price and low deposits. To commercialize SIBs similar to how LIBs already have been, it is necessary to develop improved anode materials that have high stability and capacity to operate over many and long cycles. This paper reports the development of homogeneous Sb₂S₃ nanorods (Sb₂S₃ NRs) on reduced graphene oxide (Sb₂S₃ NRs @rGO) as anode materials for SIBs. Based on this work, Sb₂S₃ NRs show a discharge capacity of 564.42 mAh/g at 100 mA/g current density after 100 cycles. In developing a composite with reduced graphene oxide, Sb₂S₃ NRs@rGO present better cycling performance with a discharge capacity of 769.05 mAh/g at the same condition. This achievement justifies the importance of developing Sb₂S₃ NRs and Sb₂S₃ NRs@rGO for SIBs.

One of the most effective cost reduction and green engineering projects is to introduce organic compounds to electrode materials instead of expensive inorganic-based materials. In this work, derivatives of perylene diimide substituted with amino acids (PDI_AAs) showed the characteristics of redox-active organic compounds and were, therefore, used as cathode materials of lithium-ion batteries (LIBs). Among the as-synthesized PDI_AAs, the L-alanine-substituted PDI (PDI_A) showed the most improved cycling performances of 86 mAhg⁻¹ over 150 cycles with retention of 95% at 50 mAg⁻¹. Furthermore, at a high current density of 500 mAg⁻¹, PDI_A exhibited a long-term cycling performance of 47 mAhg⁻¹ (retention to 98%) over 5000 cycles. In addition, ex situ attenuated total reflection Fourier-transform infrared spectroscopy (ATR FT-IR) analysis of electrodes at various charging states showed the mechanism of the charge-discharge process of PDI_A.

To address the ongoing demand for high‐performance energy storage devices, it is crucial to identify new electrode materials. Lithium‐ion batteries (LIBs) store energy via the electrochemical redox process, so their electrode materials should have reversible redox properties for rechargeability. On that note, redox‐active metal complexes are explored as innovative electrode materials for LIBs. Redox‐active metal(II) chloride complexes (MCC) demonstrate promising potential as anode materials, exhibiting high capacity and excellent rate capability. In particular, zinc(II) chloride complexes, referred to as ZCC, achieve a capacity of 1720 mAh g⁻¹ at 2.0 A g⁻¹ over 200 cycles. Additionally, the lithium‐ion storage mechanism of MCC is elucidated using ex situ analyses of MCC anode's surface in its fully discharged state. The high capacity of the MCC anode is attributed to conversion reaction with Li⁺ ions forming LiCl and electrodeposition of metallic lithium from the over‐lithiated Li⁺ ions. These findings support the potential use of redox‐active metal complexes as novel anode materials for LIBs.