Synthesis and Electrochemical Characterization of Novel Polyanion Materials for High Capacity Li-ion Battery Cathodes Synthesis and Electrochemical Characterization of Novel Polyanion Materials for High Capacity Li-ion Battery Cathodes Current cathode materials in Li-ion batteries represent the key bottleneck towards high energy density batteries for applications such as electric cars and portable electronics. The search for new cathodes has revealed that polyanion materials are promising candidates in terms of low cost, capacity, operation voltage, and safety characteristics. However, of the currently studied metal phosphates, pyrophosphates, fluorophosphates, fluorosulfates, and orthosilicates, none of these materials show the capacities> 200 mAh/g with good cycling that are required. A family of materials based on metal hydroxysulfate or hydroxyphosphate naturally occurring minerals offers the possibility for improved performance as cathode materials due to the following characteristics: (1) open framework or layered structures that can facilitate fast Li+ insertion, (2) beneficial bonding characteristics such as edge sharing MO6 octahedra for good electronic conductivity and improved rate performance, (3) flexibility in alkali and transition metal cation incorporation as observed in nature, which can allow for the design of solid-solutions to enhance structural stability, capacity, and reaction potentials, and (4) possibility for multielectron redox reactions due to the incorporation of> 1 transition metal per formula unit, which can result in capacities> 200 mAh/g. The work proposed here details a fundamental study on the synthesis, structural, and electrochemical characterization of metal hydroxysulfate and hydroxyphosphate materials for use as cathodes in Li-ion batteries. New insights into the effect of the polyanion on reaction potential and the effect of the nature chemical bonding on electronic and ionic conductivity in polyanions will also be determined.
|Effective start/end date||1/1/13 → 8/31/15|
- ACS: Petroleum Research Fund: $100,000.00
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