NASICON-structured cathode materials are considered as possible candidates for high-performance Na-ion batteries. Further increase of energy density of the Na₃V₂(PO₄)₃ may be achieved by substitution of the V cations by other transition metals. Here, we show that a family of Na_3+xMn_xV_2-x(PO₄)₃ (0≤x≤1, Δx=0.2) cathode materials demonstrates remarkable diversity of the electrochemical properties and phase transformations depending on degree of substitution and cut-off voltage. An intermediate “Na₂M₂(PO₄)₃” phase was found for all compounds studied by means of operando powder X-ray diffraction. When Mn content is low (x~0–0.4), it coexists with Na_3+xMn_xV_2-x(PO₄)₃ or Na_1+xMn_xV_2-x(PO₄)₃. Increase in Mn content extends the length of the solid solution region corresponding to sodiated, intermediate and desodiated phases. All Mn-substituted samples are characterized by additional high-voltage plateau (~3.9 V) at charge-discharge curves. Na_3+xMn_xV_2-x(PO₄)₃ (x≥0.4) compositions exhibit 8–10% energy density gain in comparison to Na₃V₂(PO₄)₃ material, Na_3.2Mn_0.2V_1.8(PO₄)₃ and Na_3.4Mn_0.4V_1.6(PO₄)₃ are most preferable in terms of cycling stability.

NASICON结构的阴极材料被认为是高性能Na离子电池的候选材料。Na ₃ V ₂（PO ₄）₃的能量密度的进一步增加可以通过用其他过渡金属取代V阳离子来实现。在这里，我们表明，Na _{3 + x} Mn _x V _2-x（PO ₄）₃（0≤x≤1，Δx= 0.2）正极材料家族表现出显着的电化学性质多样性和相变，取决于相变程度。替代和截止电压。中间体“ Na ₂ M ₂（PO ₄）₃通过操作粉末X射线衍射对所有研究的化合物均发现了“-”相。Mn含量低（x〜0-0.4）时，与Na _{3 + x} Mn _x V _2-x（PO ₄）₃或Na _{1 + x} Mn _x V _2-x（PO ₄）₃共存。Mn含量的增加延长了固溶区的长度，该固溶区的长度对应于钠化，中间和脱钠相。所有Mn取代的样品在充放电曲线上都有额外的高压平稳区（〜3.9 V）。Na _{3 + x} Mn _x V _2-x（PO ₄）与Na ₃ V ₂（PO ₄）₃材料，Na _3.2 Mn _0.2 V _1.8（PO ₄）₃和Na _3.4 Mn _0.4 V _1.6（PO ₄）相比，₃（x≥0.4）成分的能量密度增加了8-10％就循环稳定性而言，最优选₃）。