Year: 2026
Type: preprint
Abstract: Temperature is a major factor influencing battery cycle life, with elevated temperatures generally accelerating capacity degradation. Here, we employed poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS), a conductive polymer, as a binder to stabilize GaN anodes for long-term cycling at 55°C. The GaN anode with the PEDOT:PSS binder (GaN/PE) exhibits over a 40× increase in its electrical conductivity compared to the GaN anode with a conventional polyvinylidene fluoride (PVDF) binder (GaN/PVDF). The GaN/PE anode achieves a specific capacity of up to 855.3 mAh/g at 0.1 A/g, approaching the theoretical capacity of GaN (960 mAh/g) and approximately tripling the maximum capacity of the GaN/PVDF anode under the same operating conditions. In addition, the GaN/PE anode demonstrates long-term stability, retaining about 600 mAh/g after 500 cycles at 55 °C, while the GaN/PVDF anode achieves only half of that value after 500 cycles. Notably, previous reports on Si-based anodes operated within 45-70°C show a dramatic decrease in their capacity, remaining about 600 mAh/g after only 100 cycles. Molecular dynamics (MD) simulations explain the long-term stability of the GaN/PE anodes through improved thermomechanical stability of PEDOT:PSS, with a thermal expansion coefficient less than half that of PVDF, suggesting the reduction of thermal expansion mismatch within the GaN/PE anode during high-temperature operation. Operando X-ray diffraction exhibits crystalline stability in the GaN/PE anode, with less crystalline degradation than the GaN/PVDF anode. Electrochemical impedance spectroscopy (EIS) further demonstrates the stability of the GaN/PE anode, showing a 10-ohm decrease in charge-transfer resistance (Rct) after 500 cycles, whereas the GaN/PVDF anode shows an over 10× increase in Rct. . Together, our study proposes a binder technology approach that stabilizes GaN anodes by mitigating thermal degradation, enabling long-term cycling stability in LIBs for high-temperature applications.
Source: ChemRxiv
Language: English
Subfield: Electrical and Electronic Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W7214210620