Hitherto, synthesis of a single-phase Li₂MnSiO₄ has been perceived to be a challenging task owing to the formation energy possessed by different polymorphs is very close. In this context, we report a facile synthesis protocol by optimizing the synthesis conditions such as gas atmosphere, annealing temperature and time to obtain a phase pure crystalline monoclinic phase of Li₂MnSiO₄ (m-Li₂MnSiO₄)_. During the process, to avoid the formation of mixed phases of Li₂MnSiO₄, the dried precursor substance is subjected to following heat treatment conditions: (1) dried precursor is heated at ambient atmosphere followed by annealing; (2) maintaining a controlled flow of either O₂ gas purging adapting a temperature-programmed reaction (TPR). Analysis of X-ray powder patterns reveal that during the process of heat treatment, the controlled purging of O₂ is imperative to achieve battery-active monoclinic Li₂MnSiO₄. Perhaps the formation of m-Li₂MnSiO₄ occurs during the decomposition of starting material at ∼ 300 °C itself as evident from TGA/DSC analysis further annealing is essential to improve its crystallinity. The controlled flow of O₂ purging results in mono dispersion of nanoparticles (TEM analysis) whereas the conventional method of annealing leads to the agglomeration of nanoparticles. Interestingly, m-Li₂MnSiO₄ product thus obtained exhibit mesoporosity irrespective of synthesis conditions employed. The superior electrochemical performance observed in m-Li₂MnSiO₄ prepared via temperature-programmed reaction (TPR) is attributed to its higher surface area, high pore volume and mono dispersion of nanoparticles. The degradation of capacity of m-Li₂MnSiO₄ when the lower voltage is extended to 2.5 V is owing to the formation Mn₂O₃.

迄今为止，由于不同多晶型物具有的形成能非常接近，单相Li ₂ MnSiO _4的合成被认为是一项艰巨的任务。在这种情况下，我们报告了一种通过优化合成条件（例如气体气氛，退火温度和时间）来获得Li ₂ MnSiO ₄（m -Li ₂ MnSiO ₄）的纯结晶单斜晶相的简便合成方案_。在此过程中，要避免形成Li ₂ MnSiO ₄的混合相之后，将干燥的前体物质进行以下热处理条件：（1）将干燥的前体在环境气氛下加热，然后进行退火；（2）保持O ₂气体吹扫的受控流量，以适应程序升温反应（TPR）。X射线粉末图谱分析表明，在热处理过程中，必须实现O ₂的可控净化，以实现具有电池活性的单斜晶Li ₂ MnSiO ₄。可能形成m -Li ₂ MnSiO ₄从TGA / DSC分析可以看出，原料本身在约300°C的分解过程中会发生这种情况，进一步退火对于提高其结晶度至关重要。O ₂吹扫的受控流导致纳米颗粒的单分散（TEM分析），而传统的退火方法导致纳米颗粒的团聚。有趣的是，由此获得的m -Li ₂ MnSiO ₄产物表现出介孔性，而与所采用的合成条件无关。通过制备的m -Li ₂ MnSiO ₄具有优异的电化学性能。程序升温反应（TPR）归因于其较高的表面积，高孔体积和纳米颗粒的单分散性。当较低的电压延伸至2.5V时，由于形成了Mn ₂ O ₃，m -Li ₂ MnSiO ₄的容量降低。