Composite‐Structure Materials for Na‐Ion Batteries

Abstract

structure materials, [25][26][27][28][29][30][31][32][33] polyanion-based materials, [34][35][36][37][38][39][40][41][42][43][44][45][46][47][48][49][50] alloying materials, [9,[51][52][53][54][55][56] and Prussian blue analogs. [57][58][59][60][61] However, most of these developed materials are classified as single crystalline structures and exhibit limited electrochemical performances. Thus, scientists have started to think about developing a new material system that possesses the advantages of multiple materials in one material. An attractive strategy to accomplish this goal is the composite-structure material system, which has received much attention recently. [62][63][64] Compared with single-structure materials, compositestructure materials (CSMs) always exhibit better comprehensive electrochemical performance, e.g., larger reversible capacities and better cycling or rate performance. [65,66] The best example of a CSM has been studied in LIBs for many years, i.e., lithium-manganese-rich layered oxides (LLOs), [67][68][69][70] which possess both layered rhombohedral structures and mono clinic Li 2 MnO 3 -like structures. These CSMs deliver a high discharge capacity of ≈300 mAh g −1 and a high energy density of ≈1000 Wh kg −1 , which are almost two times larger than those of conventional cathode materials for LIBs.Electrode materials for NIBs are mostly derived from LIBs. Recently, some CSMs have been proposed to create NIBs with high electrochemical performance, exhibiting great potential in high-energy-density devices. However, most published CSMs are identified after the synthesis process, and few studies have been conducted on designing CSMs because of the complexity of their crystalline structure. In addition, characterizing all the structures in CSMs is more difficult than characterizing singlestructure materials. Currently, adjusting structural proportions and further balancing the electrochemical performance of CSMs still remain major challenges. Examining the literature, a detailed review of CSMs used in NIBs is lacking. In this work, research development of CSMs for NIBs is conducted based on the crystalline structure, including structure design, identification, and adjustment. Some important work and recent achievements on CSMs with a future outlook based on a mechanism analysis are also reviewed. By reviewing previous important studies on CSMs, a new electrode-material structure system for NIBs is established in this work. Structures in CSMsMost NIB electrode materials are developed based on LIB materials because the batteries have similar mechanisms. [1,3,4] Due to the growing concern of aggravated environmental problems (air pollution, global warming, etc.) and Li resources, Na-ion batteries have received significant attention as a promising alternative. Many electrode materials for Na-ion batteries have been reported in the past, especially over the past five years. However, most of these materials have a single crystalline structure and exhibit a limited electrochemical performance. Recently,...

Tailoring P2/P3 Biphases of Layered NaxMnO2 by Co Substitution for High‐Performance Sodium‐Ion Battery

“…[ 6,7 ] Normally, the layered Na x MnO 2 has three crystal structures including P2, P3, and O3, which depend on the surrounding Na environment and the number of unique oxide layers occupied within the lattice. [ 8,9 ] P2‐type Na 0.67 MnO 2 has attracted intensive attention as one of the most promising candidates due to its open diffusion channels for Na + and relatively rare phase transition. [ 10–12 ] However, this material usually suffers from strong Jahn–Teller distortion induced by the movement of the Mn 3+ O 6 in octahedron.…”

Recent Progress on the Alloy‐Based Anode for Sodium‐Ion Batteries and Potassium‐Ion Batteries

“…[ 7,8 ] Due to similar electrochemical property with Li, earth abundance, and low cost of Na and K, sodium‐ion batteries (SIBs) and potassium‐ion batteries (PIBs) have been extensively investigated and considered as the promising next generation energy storage techniques. [ 9–12 ]…”

Large Scale One-Pot Synthesis of Monodispersed Na 3 (VOPO 4 ) 2 F Cathode for Na-Ion Batteries

“…Rechargeable Na-ion batteries (NIBs) have attracted extensive attention owing to the outstanding virtues, including abundant sodium resources, low cost, and similar working principle to lithium-ion batteries (LIBs), making NIBs the promising candidate for highly efficient and large-scale energy storage systems (ESSs) [1][2][3][4]. The cathode, as the critical component determining the energy density of NIBs, has accordingly captured comprehensive attention [5][6][7].…”