98 research outputs found
Selenium Nanocomposite Cathode with Long Cycle Life for Rechargeable Li-Se Batteries
Selenium (Se) is a potential cathode material for high energy density rechargeable lithium batteries. In this study, a binderāfree Seācarbon nanotube (CNT) composite electrode has been prepared by a facile chemical method. At initial state, Se is present in the form of branched nanowires with a diameter of <150ā
nm and a length of 1ā2ā
Ī¼m, interwoven with CNTs. After discharge and reācharge, the Se nanowires are converted to nanoparticles embedded in the CNT network. This synthesis method provides a path for fabricating the Se cathodes with controllable mass loading and thickness. By studying the composite electrodes with different Se loading and thickness, we found that the electrode thickness has a critical impact on the distribution of Se during repeated cycling. Promising cycling performance was achieved in thin electrodes with high Se loading. The composite electrode with 23ā
Ī¼m thickness and 60ā% Se loading shows a high initial capacity of 537ā
mAhāgā1 and stable cycling performance with a capacity of 401ā
mAhāgā1 after 500 cycles at 1ā
C rate. This study reports a synthesis strategy to obtain Se/CNT composite cathode with long cycle life for rechargeable LiāSe batteries
Calibrating Multimodal Learning
Multimodal machine learning has achieved remarkable progress in a wide range
of scenarios. However, the reliability of multimodal learning remains largely
unexplored. In this paper, through extensive empirical studies, we identify
current multimodal classification methods suffer from unreliable predictive
confidence that tend to rely on partial modalities when estimating confidence.
Specifically, we find that the confidence estimated by current models could
even increase when some modalities are corrupted. To address the issue, we
introduce an intuitive principle for multimodal learning, i.e., the confidence
should not increase when one modality is removed. Accordingly, we propose a
novel regularization technique, i.e., Calibrating Multimodal Learning (CML)
regularization, to calibrate the predictive confidence of previous methods.
This technique could be flexibly equipped by existing models and improve the
performance in terms of confidence calibration, classification accuracy, and
model robustness
Electrochemical behavior of tin foil anode in half cell and full cell with sulfur cathode
Tin-based (Sn) metal anode has been considered an attractive candidate for rechargeable lithium batteries due to its high specific capacity, safety and low cost. However, the large volume change of Sn during cycling leads to rapid capacity decay. To address this issue, Sn foil was used as a high capacity anode by controlling the degree of lithium uptake. We studied the electrochemical behavior of Sn foil anode in half cell and full cell with sulfur cathode, including phase transform, morphological change, discharge/charge profiles and cycling performance. Enhanced cycling performance has been achieved by limiting the lithiation capacity of the Sn foil electrode. A full cell consisting of a pre-lithiated Sn foil anode and a sulfur cathode was constructed and tested. The full cell exhibits an initial capacity of 1142āÆmAh gā1 (based on the sulfur mass in the cathode), followed by stable cycling performance with a capacity retention of 550āÆmAh gā1 after 100 cycles at C/2 rate. This study reports a potential prospect to utilize Sn and S as a combination in rechargeable lithium batteries
- ā¦