Interlayer engineering of V2O5·nH2O by conductive Ni-BTA enabling high-performance aqueous ammonium ion batteries

Aqueous ammonium ion batteries (AAIBs) are of interest due to the low molar mass , small hydration radius, abundant raw materials and high safety of the carrier ammonium-ion. Nevertheless, there are numerous constraints associated with electrode materials that are suitable for ammonium-ion storage. In this study, we design and synthesize a composite comprising of one-dimensional conductive metal-organic skeleton material (1D c-MOF) embedded between layers of hydrated vanadium pentoxide (VOH) with improved ammonium-ion storage. The central ion of the 1D c-MOF is selected to be the nickel ion , while the ligand is 1,2,4,5-benzenetetramine (BTA). The incorporation of Ni-BTA between the vanadium oxide layers results in the formation of a composite (Ni-BTA/VOH) exhibiting enhanced structural stability , augmented layer spacing and elevated conductivity. Furthermore, the dual energy storage mechanisms of VOH and C N rearrangement act in concert to yield a “1+1 > 2” effect, thereby markedly enhancing the ammonium-ion storage. The specific capacity of Ni-BTA/VOH can reach 183 mAh g −1 at 0.2 A g −1 , and the retention rate can reach 52.5 % after 500 cycles at 2 A g −1 . This work not only proves the potential of Ni-BTA/VOH for widespread application in the field of aqueous batteries , but also provides a new method for structural engineering of VOH with boosted ammonium-ion storage properties. • Ni-BTA/VOH was designed and synthesized as electrode material for ammonium-ion storage applied to AAIBs. • The dual energy storage mechanism of VOH and C N rearrangement synergistically produces a ‘1 + 1>2’ effect. • The PTCDI//Ni-BTA/VOH full battery shows great potential for practical applications in AAIBs.