TiS2 as an Advanced Conversion Electrode for Sodium‐Ion Batteries with Ultra‐High Capacity and Long‐Cycle Life

Titanium disulfide (TiS2) is investigated as an advanced conversion electrode for sodium (Na)‐ion batteries (NIB) in an ether‐based electrolyte (NaPF6/glyme (DME)). The as‐prepared TiS2 demonstrates a high reversible capacity of 1040 mA h g−1 at 0.2 A g−1 with the capacity contribution of 521 mA h g−1 in the voltage region below 1.0 V (vs Na/Na+), remarkable initial coulombic efficiency of 95.9% and superior rate capability of 621 mA h g−1 at 40 A g−1. The high conductivity of the Ti‐based compounds and nanosized particles generated by chemical conversion reactions could minimize the entropic barrier for the reversible conversion, resulting in high reversibility and ultrafast charge/discharge ability of the electrode. Moreover, with its strong ability to adsorb soluble polysulfide intermediates, the as‐prepared TiS2 electrode exhibits superior cycling stability over 9000 cycles, serving as a stable and ultra‐high capacity conversion electrode for NIBs.