Enabling One‐Step De‐Sodiation of Na₄MnV(PO₄)₃ Cathode via Regulating Coordination Environment for High‐Power and Long‐Lasting Sodium‐Ion Batteries

Abstract Na 4 MnV(PO 4 ) 3 (NMVP) is considered as a promising cathode candidate for sodium‐ion batteries (SIBs) because it possesses a higher voltage plateau of 3.6 V (Mn 3+ /Mn 2+ ) besides the voltage plateau of 3.4 V (V 4+ /V 3+ ), lower cost, and environmental benign compared to Na 3 V 2 (PO 4 ) 3 . However, such cathode still suffers from sluggish intrinsic Na + diffusion kinetics and the Jahn‐Teller distortion of Mn 3+ , leading to low capacity and poor cycling performance. Particularly, the second‐step Na + de‐sodiation in NMVP is the rate‐determining step owing to a lower chemical diffusion coefficient with one order of magnitude than that of the first‐step counterpart. To address these issues, a coordination environment regulation strategy is reported to develop a one‐step de‐sodiation NMVP cathode via introducing Zr 4+ and K + /Ca 2+ into Mn and Na sites, respectively. Based on theoretical calculations and electrochemical evaluation, the obtained Na 3.3 K 0.1 Ca 0.1 Mn 0.8 VZr 0.2 (PO 4 ) 3 exhibits much enhanced Na + diffusion and efficiently inhibits the Jahn‐Teller distortion. Importantly, such modification significantly facilitates the second‐step Na + diffusion of NMVP, realizing one‐step de‐sodiation. When employed as a cathode for SIBs, such cathode shows a specific capacity of 73 mAh g −1 (15 C), and capacity retentions of 92.7% after 3000 cycles (at 10 C, room temperature), and 72.6% after 1000 cycles (1 C, 50 °C).