Huawei announced a major breakthrough in its research into Li-ion batteries, unveiling the world's first long-lifespan graphene-assisted Li-ion battery able to withstand high temperatures. Huawei's research results show that new graphene-based heat-resistant technologies allow Li-ion batteries to remain functional in a 60°C environment, a temperature 10°C higher than the existing upper limit. The lifespan of the graphene-assisted Li-ion batteries will also be twice as long as ordinary Li-ion batteries.
Source: http://www.huawei.com/en/news/2016/12/Graphene-Assisted-Li-ion-Batteries