Battery materials for ultrafast charging and discharging
Battery materials for ultrafast charging and discharging
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DOI：
10.1038/nature07853
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发表时间：
2009-03-12
期刊：
影响因子：
64.8
通讯作者：
Ceder, Gerbrand
中科院分区：
文献类型：
--
作者：
Kang, Byoungwoo;Ceder, Gerbrand
高充放电率下的电能存储是当今社会的一项重要技术，可以实现混合动力和插电式混合动力电动汽车，并为风能和太阳能提供备用。人们通常认为，在电化学系统中，只有超级电容器才能实现非常高的功率速率，超级电容器以高功率换取低能量密度，因为它们仅通过电极材料上带电物质的表面吸附反应来存储能量(1-3)。在这里，我们表明，通过在大量材料中存储电荷来获得高能量密度的电池（4,5）也可以实现与超级电容器相当的超高放电率。我们在 LiFePO4（参考文献 6）（一种具有高锂本体迁移率 (7,8)）的材料中实现了这一点，通过受控的非化学计量创建快速离子传导表面相。可以实现相当于 10-20 秒内电池完全放电的倍率能力。
The storage of electrical energy at high charge and discharge rate is an important technology in today's society, and can enable hybrid and plug-in hybrid electric vehicles and provide back-up for wind and solar energy. It is typically believed that in electrochemical systems very high power rates can only be achieved with supercapacitors, which trade high power for low energy density as they only store energy by surface adsorption reactions of charged species on an electrode material(1-3). Here we show that batteries(4,5) which obtain high energy density by storing charge in the bulk of a material can also achieve ultrahigh discharge rates, comparable to those of supercapacitors. We realize this in LiFePO4 (ref. 6), a material with high lithium bulk mobility(7,8), by creating a fast ion-conducting surface phase through controlled off-stoichiometry. A rate capability equivalent to full battery discharge in 10-20 s can be achieved.