In Situ Secondary Phase Modified Low-Strain Na₃Ti(PO₃)₃N Cathode Achieving Fast Kinetics and Ultralong Cycle Life

Abstract

Titanium-based polyanionic materials have attracted extensive studies in recent decades due to their prominent advantages of outstanding structural stability and low cost, which make them promising electrode materials in sodium-ion batteries (SIBs). However, their electrochemical performance is usually limited by an inherently low electronic conductivity. Herein, the NaTi2(PO4)3 (NTP) phase is introduced into the Na3Ti­(PO3)3N (NTMN) phase and shows outstanding cycling stability (high-capacity retention of 96.04% at 5 C after 4500 cycles) and enhanced rate performance (∼1.5 times higher capacity in comparison to the undecorated sample at 5 C). Comprehensive in situ/ex situ characterizations reveal an ideal single-phase transition mechanism with a tiny lattice volume distortion (∼0.53%) of NTMN. Density functional theory (DFT) calculations illustrate the Na+ diffusion acceleration mechanism of NTP in the NTMN material. This work provides a promising process to synthesize nitridophosphate materials and offers an effective in situ strategy to improve the electrochemical performance of the as-synthesized materials.

Nanosheet-Assembled Hierarchical Petal-like Na4MnV(PO4)3@Carbonized-Polyaniline Microspheres for Stable Sodium-Ion Batteries

“…The peaks situated at 19.4°, 19.8°, 22.9°, 31.5°, and 34.2°are indexed to (2-10), ( 104), (2-13), (2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16), and (300) facets, respectively. Evidently, the phenomenon of a right shift occurs for all the peaks, especially (104), (2-13), (2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16), and (300) peaks (right side of Figure 4e) during the charging process up to 3.6 V, corresponding to solid-solution reaction for V 4+ /V 3+ redox (Na 4 MnV(PO 4 ) 3 → Na 3 MnV(PO 4 ) 3 ). 28,29,53 When the voltage is near 3.8 V, the (2-10) and (104) peaks almost combine into one, which can be ascribed to a biphasic transition for Mn 3+ /Mn 2+ (Na 3 MnV-(PO 4 ) 3 → Na 2 MnV(PO 4 ) 3 ).…”

“…Thus, ex situ XRD was performed during the initial charge/discharge process, and the pattern is depicted in Figure 4e. The peaks situated at 19.4°, 19.8°, 22.9°, 31.5°, and 34.2°are indexed to (2-10), ( 104), (2-13), (2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16), and (300) facets, respectively. Evidently, the phenomenon of a right shift occurs for all the peaks, especially (104), (2-13), (2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16), and (300) peaks (right side of Figure 4e) during the charging process up to 3.6 V, corresponding to solid-solution reaction for V 4+ /V 3+ redox (Na 4 MnV(PO 4 ) 3 → Na 3 MnV(PO 4 ) 3 ).…”

“…For the world’s better transition to a green economy, it is particularly key to develop advanced energy storage and conversion systems. , Exploiting a rechargeable battery with long cycling life and high energy density is critical to the advances of novel energy storage systems (ESSs). , Despite the widespread use of lithium-ion batteries (LIBs) in various fields of electronic devices, their limited availability and cost prevented them from being applied in large-scale ESSs. − Naturally, high-performance sodium-ion batteries (SIBs) are suitable for development in alternative ESSs due to the lower cost, abundant resources, and similar physicochemical mechanism to LIBs. − Therefore, it is urgent to advance cathode electrodes with high-rate performance and stable lifespan, which largely dominate the SIB performance advancement. , …”

Nitrogen as An Anionic Center/Dopant for Next‐Generation High‐Performance Lithium/Sodium‐Ion Battery Electrodes: Key Scientific Issues, Challenges and Perspectives

“…Reproduced with permission. [ 69 ] Copyright 2022, American Chemical Society. h) Formation energy of Na 3‐ x Ti 0.5 V 0.5 (PO 3 ) 3 N material based on the DFT calculation.…”

Zn/Ti/F synergetic-doped Na0.67Ni0.33Mn0.67O2 for sodium-ion batteries with high energy density

“…4,5 Cathode materials for SIBs mainly include layered oxides, 6,7 tunnel oxides, 8,9 analogues of Prussian blue 10,11 and NASICON. 12,13 Layered oxides have become popular choices for cathodes thanks to their high energy density and rich variety. Based on the arrangement of Na + between TMO 6 layers, layered oxides Na x -TMO 2 (TM = Co, Fe, Mn, Ni, Cr) were rst classied into two groups by Delmas et al, 14 including P2-type (Na + occupying trigonal prismatic sites) and O3-type (Na + occupying octahedral sites).…”