科研之友
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摘要
The urgent need for next generation lithium-ion batteries requires cathode materials with higher energy and power density. Though Li-rich layered materials deliver much higher capacity than their commercial counterparts, there is still a pressing need for easy and effective methods to break through the Li-ion transport barrier, which results from cation rearrangement during the Li2MnO3 activation process. Herein, an interfacial framework of spinel structure is built by ion exchange with thermal treatment to boost mass transport of Li-rich materials. The newly formed spinel phase is derived within the layered crystal framework, enabling its intimate integration with the bulk structure. This design not only stabilizes the interface, but also ensures rapid mass transport due to its 3D diffusion channels, ultimately breaking through the Li-ion transport barrier. The charging time could be reduced to one-tenth after modification, without compromising the discharging capacity. Remarkably, the discharge capacity (219.6 mA h g(-1)) obtained at a 10C rate is up to 82.9% and 79.1% of that obtained at 1C and 0.1C rates, respectively, and the initial coulombic efficiency at the 0.1C rate is greater than 90%. This approach is simple, efficient and able to be applied to other analogous layered manganese-based materials. We anticipate that this strategy will pave new ways to counter the sluggish Li-ion transport of layered electrode materials.
- 出版日期2017-12-14
- 单位北京理工大学
