A High-Rate Manganese Oxide for Rechargeable Lithium Battery Applications

Abstract
LixMnO2LixMnO2 made by ion exchange of glycine-nitrate combustion synthesis-processed (GNP) orthorhombic Na0.44MnO2Na0.44MnO2 (GNP­LixMnO2)(GNP­LixMnO2) has been cycled in lithium/liquid electrolyte cell configurations at room temperature and lithium/polymer cell configurations at 85°C over one hundred times without showing capacity fading or phase conversion to spinel. At 2.5 mA/cm2 in liquid cells (5C rate) or 1 mA/cm2 (1.5C rate) in polymer cells, 80-95% of the expected capacity is delivered. The remarkable stability is attributable to the unusual double tunnel structure, which cannot easily undergo rearrangement to spinel. The enhanced rate capability of GNP­LixMnO2GNP­LixMnO2 compared to conventionally prepared materials is attributable to the shorter particle length, which allows faster diffusion of lithium ions along the tunnels. © 2001 The Electrochemical Society. All rights reserved.