Lithium metal could be a high-capacity anode material for rechargeable batteries. However, during charge/discharge cycles, the metal forms so-called dendrites, tree-like structures which can grow and cause dangerous short circuits. In addition, the larger surface area caused by dendrite formation makes side reactions between lithium and the electrolyte more likely.
Qiang Zhang,Tsinghua University, Beijing, China, Yury Gogotsi, Drexel University, Philadelphia, PA, USA, and colleagues have used nanodiamonds as an electrolyte additive to prevent the formation of lithium dendrites. The team used nanodiamond particles produced by a commercial detonation method, and modified them by carboxylation and covalent linking to octadecylamine (ODA). The particles were then dispersed in an ester-based electrolyte and tested in lithium cells.
The researchers found that the lithium ions in the cells are deposited onto the substrate together with nanodiamond particles. This produces uniformly distributed lithium. The team proposes that this effect is caused by the higher tendency of Li ions to adsorb onto the nanodiamond surface compared with the substrate of the anode. This lessens lithium aggregation and produces a dendrite-free morphology. The addition of nanodiamonds improves the electrochemical cycling stability of lithium batteries, with stable performance over hundreds of cycles, as well as their safety.
- Nanodiamonds suppress the growth of lithium dendrites,
Xin-Bing Cheng, Meng-Qiang Zhao, Chi Chen, Amanda Pentecost, Kathleen Maleski, Tyler Mathis, Xue-Qiang Zhang, Qiang Zhang, Jianjun Jiang, Yury Gogotsi,
Nat. Commun. 2017.