Engineering topics
Liu, Gao (ORCID:0000000168860507)
Publications and source records attributed to Liu, Gao (ORCID:0000000168860507).
Critical Evaluation of Potentiostatic Holds as Accelerated Predictors of Capacity Fade during Calendar Aging
Li-ion batteries will lose both capacity and power over time due to calendar aging caused by slow parasitic processes that consume Li + ions. Studying and mitigating these processes is traditionally an equally slow venture, which is especially taxing for the validation of new active materials and electrolyte additives. Here, we evaluate whether potentiostatic holds can be used to accelerate the diagnosis of Li + loss during calendar aging. The technique is based on the idea that, under the right conditions, the current measured as the cell voltage is held constant can be correlated with the instantaneous rate of side reactions. Thus, in principle, these measurements could capture the rate of capacity fade in real time . In practice, we show that this method is incapable of quantitatively forecasting calendar aging trends. Instead, our study demonstrates that potentiostatic holds can be applied for initial qualitative screening of systems that exhibit promising long-term stability, which can be useful to shrink the parameter space for calendar aging studies. By facilitating the identification of improved formulations, this approach can help accelerate innovation in the battery industry.
Electrolyte decomposition and solid electrolyte interphase revealed by mass spectrometry
Not Available
Viscosity Analysis of Battery Electrode Slurry
We report the effects of component ratios and mixing time on electrode slurry viscosity. Three component quantities were varied: active material (graphite), conductive material (carbon black), and polymer binder (carboxymethyl cellulose, CMC). The slurries demonstrated shear-thinning behavior, and suspension properties stabilized after a relatively short mixing duration. However, micrographs of the slurries suggested their internal structures did not stabilize after the same mixing time. Increasing the content of polymer binder CMC caused the greatest viscosity increase compared to that of carbon black and graphite.
Communication—Functional Conductive Polymer Binder for Practical Si-Based Electrodes
Multifunctional conductive binders represent an emerging class of polymer materials to address inherent challenges of Si electrodes for high capacity lithium-ion batteries. Advanced binders with oriented functionalities are greatly desired to facilitate the battery chemistry. We here report stable capacity cycling of a practical composite anode comprising industrial available SiO x (>60 wt%), carbon materials and a conductive polymer binder—poly(9,9-dioctylfluorene- co -fluorenonecomethylbenzoic ester) (PFM). This multifunctional polymer functions as both an interface modifier and an electrode binder for high-performing SiO x composite electrodes. The viability of multifunctional conductive polymer binders was further validated in a practical full cell.