Zeng, JingyaoGao, JinqiangJian, WeishunWang, HaojiLi, WenyuanHong, NingyunZhang, Baichao2026-04-042026-04-0420241616-301X1616-3028https://doi.org/10.1002/adfm.202410992https://hdl.handle.net/11616/110022Na4Mn1.5Fe1.5(PO4)(2)P2O7 (NMFPP), with its low cost and high energy density, is essential for accelerating the commercialization of sodium-ion batteries. However, its practical application is limited by serious voltage hysteresis and detrimental Jahn-Teller distortions. Herein, a high operating voltage and superior stable Nb-doped NMFPP with fewer intrinsic anti-site defects are elaborately designed by the reconstruction of the crystal lattice and electronic distribution. By introducing higher charge density Nb & horbar;O bonds, the lengths of Mn-O bonds are shortened, enhancing lattice stability. As a result, the lattice volume contracted during Na+ extraction/insertion is decreased with niobium-modified Na-4(Mn0.5Fe0.5)(2.94)Nb-0.06(PO4)(2)P2O7, mitigating lattice distortion from the Jahn-Teller effect and increasing the capacity retention after 1000 cycles from 57.5% to 82.3%. More importantly, the delayed effect of Mn2+ involvement in redox reactions is significantly reduced, raising the average operating voltage from 3.32 to 3.64 V and increasing the overall energy density by 13%. This study opens new avenues to develop advanced sodium-ion battery cathode materials with high energy density and long calendar life for energy storage.eninfo:eu-repo/semantics/openAccessJahn-Teller effectmanganese-iron-baseNASICON cathodevoltage hysteresisArticle345210.1002/adfm.2024109922-s2.0-85200728598Q1WOS:001287516600001Q10000-0001-8201-4614