Research press release


Nature Energy

Switching to safer batteries



Yi CuiとZhenan Baoたちは、グラフェンをコーティングした棘だらけのニッケルナノ粒子をポリエチレンプラスチックに混合した複合材料を開発した。加熱すると、プラスチックが膨張して導電性のニッケルナノ粒子が離れ、この材料の導電率が迅速に大きく(1秒で7~8桁)低下する。その後冷却すると、プラスチックが収縮して、この材料の導電率は元に戻る。Cuiたちは、この熱応答性の高い材料を用いてリチウムイオン電池の集電極をコーティングし、温度変化に対してこれまでのスイッチングデバイスより著しく高い感度を実現できることを実証した。


A material that can rapidly shut down an overheating lithium-ion battery and quickly restore the battery’s function as it cools is reported in a paper published online in Nature Energy this week. The highly thermoresponsive material may help to ensure the safe operation of rechargeable batteries.

Overheating is a common fire hazard caused by the overcharging of rechargeable batteries or internal electrical shorting.

Yi Cui, Zhenan Bao and colleagues developed a composite material that consists of graphene-coated spiky nickel nanoparticles mixed in a polyethylene plastic network. Upon heating, the plastic expands and separates the conductive nickel nanoparticles, which rapidly and substantially decreases the material’s conductivity (by 7-8 orders of magnitude in one second). After cooling, the plastic contracts and the material rapidly recovers its original conductivity. The authors used this highly thermoresponsive material to coat the current collectors in lithium-ion batteries and demonstrated that their approach achieves significantly higher sensitivity to temperature changes than previous switching devices.

The authors suggest that their method may improve future battery design and safety features. However, further research is required to determine whether the material can be applied to large-scale batteries, such as those used in electric vehicles.

doi: 10.1038/nenergy.2015.9


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