Organic Pre‐Intercalator with Weak Interaction to Host Lattice for High‐Performance Zn Ion Batteries

Abstract Pre‐intercalation engineering is effective in promoting the intercalation kinetics of Zn ions in vanadium oxide host lattices. However, the practical capacities of pre‐intercalated vanadium oxides are still far below their theoretical values, and this disparity is not clear yet. Herein, methylammonium ions (CH 3 NH 3 + ) are reported as an organic pre‐intercalant into vanadium oxides, achieving a remarkable practical capacity of 472.0 mAh g −1 , corresponding to an exceptionally high practical‐to‐theoretical capacity ratio of 87.71%. It is identified that the apical lattice‐oxygens are the preferential storage sites for (de)inserted Zn 2+ via in situ/ex situ characterizations and theoretical calculations. The results indicate that organic ions connect to the host lattice primarily via weak hydrogen‐bond interactions, rather than strong coordination bonds by previous pre‐intercalated inorganic ions, so more accessible ion‐insertion sites remain unoccupied to achieve a higher capacity near theoretical values. Moreover, the CH 3 NH 3 + ions can promote proton transport, delivering a high rate‐capability (20 A g −1 ). This pre‐intercalation strategy also realizes ultra‐long lifespan (20 000 cycles) and stable Ah‐scale (0.69 Ah) cell tests. The work provides an insightful understanding of the intercalation chemistry of Zn ions and practical approaches for high‐energy Zn‐ion batteries.