Department of Materials Science and Engineering, CAS Key Laboratory of Materials for Energy Conversion, iChEM, University of Science and Technology of China, Hefei, Anhui, 230026, P. R. China.
School of Chemistry and Chemical Engineering, Hefei University of Technology, Hefei, 230009, China.
Adv Mater. 2017 Oct;29(38). doi: 10.1002/adma.201700783. Epub 2017 Aug 21.
Lithium metal is an attractive anode material for rechargeable batteries because of its high theoretical specific capacity of 3860 mA h g and the lowest negative electrochemical potential of -3.040 V versus standard hydrogen electrode. Despite extensive research efforts on tackling the safety concern raised by Li dendrites, inhibited Li dendrite growth is accompanied with decreased areal capacity and Li utilization, which are still lower than expectation for practical use. A scaffold made of covalently connected graphite microtubes is reported, which provides a firm and conductive framework with moderate specific surface area to accommodate Li metal for anodes of Li batteries. The anode presents an areal capacity of 10 mA h cm (practical gravimetric capacity of 913 mA h g ) at a current density of 10 mA cm , with Li utilization of 91%, Coulombic efficiencies of ≈97%, and long lifespan of up to 3000 h. The analysis of structure evolution during charge/discharge shows inhibited lithium dendrite growth and a reversible electrode volume change of ≈9%. It is suggested that an optimized microstructure with moderate electrode/electrolyte interface area is critical to accommodate volume change and inhibit the risks of irreversible Li consumption by side reactions and Li dendrite growth for high-performance Li-metal anodes.
金属锂因其高达 3860 mA h g 的理论比容量和相对于标准氢电极的最低负电化学电位-3.040 V，是一种很有吸引力的可充电电池阳极材料。尽管人们在解决由锂枝晶引起的安全问题方面进行了广泛的研究，但受限于抑制锂枝晶生长，其比容量和锂利用率会降低，这仍然低于实际应用的预期。本文报道了一种由共价连接的石墨微管组成的支架，它提供了一个坚固且导电的框架，具有适中的比表面积，可容纳锂金属作为锂电池的阳极。该阳极在 10 mA cm 的电流密度下具有 10 mA h cm 的面积容量（实际重量容量为 913 mA h g），锂利用率为 91%，库仑效率约为 97%，寿命长达 3000 小时。对充放电过程中结构演变的分析表明，抑制了锂枝晶的生长，电极体积变化可逆约为 9%。研究表明，对于高性能的锂金属阳极，具有适中的电极/电解质界面面积的优化微结构对于适应体积变化和抑制副反应不可逆消耗锂和锂枝晶生长的风险至关重要。
