Related Experiment Video
Updated: Aug 15, 2026
09:04
Fabrication of VB2/Air Cells for Electrochemical Testing
Published on: August 5, 2013
Coupling Water-Driven Amorphization With High Entropy Strategy in Vanadium Oxide Cathodes for High-Capacity and
Maoyu Sun1, Qi Zhang1, Fayin Liu1
1Faculty of Chemistry, Northeast Normal University, Changchun, P. R. China.
Angewandte Chemie (International Ed. in English)
|August 13, 2026
Summary
Aqueous potassium-ion batteries benefit from water-induced amorphous transitions, but stability is key. A high-entropy doped amorphous vanadium oxide cathode enhances capacity and durability for advanced energy storage.
Area of Science:
- Electrochemistry
- Materials Science
- Energy Storage
Background:
- Aqueous potassium-ion batteries (APIBs) offer safe, cost-effective large-scale energy storage.
- Developing stable cathodes is challenging due to K+ ion size and water's erosive effects.
- Crystalline V2O5 cathodes undergo water-mediated amorphization, increasing capacity but reducing stability.
Purpose of the Study:
- Investigate the mechanism of water's role in V2O5 cathode cycling.
- Develop a stable and high-performance cathode for APIBs using a mechanism-guided design.
- Address the bottlenecks of lattice strain and electrode instability in APIBs.
Main Methods:
- Systematic investigation of crystalline V2O5 cycling mechanism.
- Synthesis of high-entropy doped amorphous vanadium oxide (HE-AVO) cathode.
- In-situ spectroscopy, ex-situ time-of-flight secondary ion mass spectrometry, and theoretical calculations.
Main Results:
- Water acts as 'chemical scissors,' inducing crystal-to-amorphous transition in V2O5, enhancing capacity.
- HE-AVO cathode achieved 110.4 mAh·g-1 specific capacity.
- HE-AVO demonstrated exceptional cycling stability, retaining 97.3% capacity over 30,000 cycles at 5 A·g-1.
- High-entropy doping suppressed vanadium dissolution and maintained a disordered network.
Conclusions:
- Clarified the water-mediated amorphization mechanism in V2O5 cathodes.
- High-entropy strategy effectively enhances electrode stability and electrochemical performance.
- Established a viable pathway for designing durable, high-rate electrodes for aqueous batteries.
Related Concept Videos
03:12Batteries and Fuel Cells
A battery is a galvanic cell that is used as a source of electrical power for specific applications. Modern batteries exist in a multitude of forms to accommodate various applications, from tiny button batteries such as those that power wristwatches to the very large batteries used to supply backup energy to municipal power grids. Some batteries are designed for single-use applications and cannot be recharged (primary cells), while others are based on conveniently reversible cell reactions that...
03:00Electrolysis
In a galvanic cell, the electrical work is done by a redox system on its surroundings as electrons produced by the spontaneous redox reactions are transferred through an external circuit. Alternatively, an external circuit does work on a redox system by imposing a voltage sufficient to drive an otherwise nonspontaneous reaction in a process known as electrolysis. For instance, recharging a battery involves the use of an external power source to drive the spontaneous (discharge) cell reaction in...
02:47Voltaic/Galvanic Cells
Spontaneous Chemical Reactions
Spontaneous redox reactions occur abundantly in nature. The chemical reaction occurring in a disposable AA battery powering our remote controls is one such example of a spontaneous redox reaction. Another example is the immersion of coiled copper wire into an aqueous silver nitrate solution. The reaction shows a gradual, visually impressive color change from colorless to bright blue and the formation of a grey precipitate on the copper wire. In this experiment,...
Spontaneous redox reactions occur abundantly in nature. The chemical reaction occurring in a disposable AA battery powering our remote controls is one such example of a spontaneous redox reaction. Another example is the immersion of coiled copper wire into an aqueous silver nitrate solution. The reaction shows a gradual, visually impressive color change from colorless to bright blue and the formation of a grey precipitate on the copper wire. In this experiment,...
03:08Electrolytes: van't Hoff Factor
Colligative Properties of ElectrolytesThe colligative properties of a solution depend only on the number, not on the identity, of solute species dissolved. The concentration terms in the equations for various colligative properties (freezing point depression, boiling point elevation, osmotic pressure) pertain to all solute species present in the solution. Nonelectrolytes dissolve physically without dissociation or any other accompanying process. Each molecule that dissolves yields one dissolved...
01:28Electrochemical Cells
Electrochemical cells are systems that convert chemical energy into electrical energy or use electrical energy to drive chemical reactions. They consist of two electrodes in contact with an electrolyte, where redox reactions enable electron transfer. Most electrochemical cells include two half-cells connected by an external wire for electron flow and a salt bridge for ion flow. The salt bridge contains an electrolyte solution and maintains charge neutrality by allowing ions—not electrons—to...
01:19Ionic Strength: Effects on Chemical Equilibria
The addition of an inert ionic compound increases the solubility of a sparingly soluble salt. For example, adding potassium nitrate to a saturated solution of calcium sulfate significantly enhances the solubility of calcium sulfate. Le Châtelier's principle cannot predict this shift in the equilibrium. Instead, this could be explained in terms of changes in the effective concentration of the ions in solution in the presence of added inert salt.
In this solution, the primary cation—the calcium...
In this solution, the primary cation—the calcium...