Expanding the chemical space for designing novel anionic redox materials from oxides to sulfides has enabled to better apprehend fundamental aspects dealing with cationic-anionic relative band positioning. Pursuing with chalcogenides, but deviating from cationic substitution, we here present another twist to our band positioning strategy that relies on mixed ligands with the synthesis of the Li₂TiS_3-xSe_x solid solution series. Through the series the electrochemical activity displays a bell shape variation that peaks at 260 mAh/g for the composition x = 0.6 with barely no capacity for the x = 0 and x = 3 end members. We show that this capacity results from cumulated anionic (Se²⁻/Seⁿ⁻) and (S²⁻/Sⁿ⁻) and cationic Ti³⁺/Ti⁴⁺ redox processes and provide evidence for a metal-ligand charge transfer by temperature-driven electron localization. Moreover, DFT calculations reveal that an anionic redox process cannot take place without the dynamic involvement of the transition metal electronic states. These insights can guide the rational synthesis of other Li-rich chalcogenides that are of interest for the development of solid-state batteries.

扩大用于设计从氧化物到硫化物的新型阴离子氧化还原材料的化学空间，能够更好地理解处理阳离子 - 阴离子相对带定位的基本方面。追求硫属化物，但与阳离子取代不同，我们在这里提出了对我们的带定位策略的另一种转变，该策略依赖于混合配体与 Li ₂ TiS _3-x Se _x固溶体系列的合成。在整个系列中，电化学活性显示出钟形变化，对于组合物x  = 0.6，在 260 mAh/g 处达到峰值，而x  = 0 和x  = 3 末端成员几乎没有容量。我们表明这种容量是由累积的阴离子（Se^2- /Se ^n- ) 和 (S ^2- /S ^n- ) 和阳离子 Ti ³⁺ /Ti ⁴⁺氧化还原过程，并为通过温度驱动的电子定位进行金属-配体电荷转移提供证据。此外，DFT 计算表明，如果没有过渡金属电子态的动态参与，阴离子氧化还原过程就不会发生。这些见解可以指导对固态电池开发感兴趣的其他富锂硫属化物的合理合成。