They claim to have developed a novel aluminum-graphene battery that is more cold-resistant, can work in temperatures ranging from -40 C to 120 C and is less flammable.
The battery, which has a positive pole made up of graphene thin film and a negative pole of aluminum, can retain 91 percent of its capacity even after 250,000 charge/discharge circles, a marked improvement compared with the lithium battery.
Rechargeable aluminum-ion batteries are promising in high-power density but still face critical challenges of limited lifetime, rate capability, and cathodic capacity. We design a “trihigh tricontinuous” (3H3C) graphene film cathode with features of high quality, orientation, and channeling for local structures (3H) and continuous electron-conducting matrix, ion-diffusion highway, and electroactive mass for the whole electrode (3C). Such a cathode retains high specific capacity of around 120 mAh g−1 at ultrahigh current density of 400 A g−1 (charged in 1.1 s) with 91.7% retention after 250,000 cycles, surpassing all the previous batteries in terms of rate capability and cycle life. The assembled aluminum-graphene battery works well within a wide temperature range of −40 to 120°C with remarkable flexibility bearing 10,000 times of folding, promising for all-climate wearable energy devices. This design opens an avenue for a future super-batteries.
If a smartphone used such a super battery, it would last up to 70 years without losing its capacity, even with 10 charges every day. In terms of charging time, the super battery, when used by a smartphone, could be charged in 5 seconds and used as long as two hours, the research team said.
But industry expert Zheng Jiatu, deputy managing director of the China Electric Vehicle Charging Technology and Industry Alliance, said he is doubtful of the results published by the team.
“These figures must be read with some caution,” Zheng said, noting that even testing 250,000 charge/discharge cycles would itself take a very long time.
“The announced results are more likely the results of a simulated data model, rather than results from prototype testing,” Zheng said.
The team said there is a long way ahead, with many obstacles to overcome before commercialization. They also said that the “super” battery is inferior to the lithium battery in terms of energy intensity.