page_title: Lithium hybrid organic battery
section_title: PAni/V2O5
hierarchical_section_title: Lithium hybrid organic battery / PAni/V2O5
caption_attribution_description: English: Figure 1 for Chem171
context_page_description: Lithium hybrid organic batteries are an energy storage device that combines lithium with an organic polymer. For example, polyaniline vanadium (V) oxide can be incorporated into the nitroxide-polymer lithium iron phosphate battery, PTMA/LiFePO₄. Together, they improve the lithium ion intercalation capacity, cycle life, electrochemical performances, and conductivity of batteries.
context_section_description: Oxides, like V₂O₅, are used as cathodes in rechargeable lithium batteries. Crystalline V₂O₅ has a weaker rechargeability or cyclability than amorphous V₂O₅ because the crystal structure is damaged during discharge/charge cycles. However, amorphous oxides, in particular the V₂O₅ xerogel, allows lithium ions to diffuse faster and thus have a better cyclability. Hybrid is formed by combining a conducting organic polymer (e.g. polyaniline) with an oxide (e.g. V₂O₅).
  V₂O₅ gels are prepared using the ion-exchange method. Vanadium (V) polymerizes aniline. Before synthesis of a hybrid battery, potentiometric titration of V₂O₅ gel with  is carried out; this determines the amount of V(V) present in the gel. Aniline solution is slowly added onto the  gel. The following procedure is demonstrated in Figure 3. 
  V₂O₅ is used because of its high specific capacity, high thermal stability, and high structural flexibility with lithium. Up to three moles of lithium ions can be added into the V₂O₅ lattice to create different structures. The structures created give the hybrid a long battery life. However, the intercalation capacity depends on the moderate electrical conductivity and low diffusion coefficient of the lithium ions in the vanadium oxide matrix.
  Polyaniline is easily produced to have controlled structural and electronic properties. Polyaniline eliminates the coordinated water of the V₂O₅ xerogel, so more lithium ions can be integrated into the structure. The organic part of the PAni/V₂O₅ hybrid degrades with the increase of temperature.
  V(V) is reduced to V(IV), and aniline is oxidized to polyaniline. Re-oxidizing V(IV) to a higher oxidation state of V(V) increases initial cell voltage and specific capacity. Since polyaniline is an electrochemically active component, it improves the specific charge of the hybrid material.  Combining polyaniline with V₂O₅ yields a larger specific charge difference. Thus, a greater total capacity contribution than V₂O₅ alone. Furthermore, the hybrid has a higher specific capacity than that of the V₂O₅ xerogel. Electrical conductivity is as high as 0.09 S/cm for 15 days.
  As a result, PAni/V₂O₅ hybrid is a conducting network and an electroactive material in the composites, which improves electrochemical behavior. It also prevents the irreversible structural changes made by redox cycling when the lithium ions enter the lattice. Moreover, this hybrid also has a high specific capacity and improved cyclability without capacity deterioration.
caption: Figure 1: Diagram of charging and discharging of hybrid battery
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