Du Guangyuan, Gao Aosong, Qian Guoyu, Lu Xueyi, Xie Fangyan, Lu Xia
School of Materials, Sun Yat-sen University, Shenzhen, 518107, P. R. China.
Instrumental Analysis & Research Center, Sun Yat-sen University, Guangzhou, 510275, P. R. China.
Small. 2024 Nov;20(46):e2404992. doi: 10.1002/smll.202404992. Epub 2024 Aug 7.
It is generally accepted that the low-temperature environment typically augments electrolyte viscosity and impedes electrochemical kinetics, thereby diminishing battery performance. However, this prevailing notion, while valid in certain contexts, lacks universality, particularly regarding cycling stability. In this context, the Na-MoS batteries serve as a model to elucidate the impacts of low temperatures. By significantly suppressing the pulverization and amorphization of MoS, the low-temperature milieu effectively mitigates the risk of micro-short circuits induced by the mass shuttling to the Na metal anode, thereby averting performance degradation by self-discharge. Upon cycling, the generated NaMoS intermediates only at low temperatures benefit the structural and electrochemical stabilizations to counteract the intrinsic performance degradation. The attenuation of kinetics at low temperatures facilitates the accumulation of NaS, akin to a sustained-release agent within the electrode, steadily furnishing the capacity in long cycling. Moreover, the suppression of polysulfide dissolution and shuttling emerges as a pivotal factor contributing to the cycling stability at low-temperature. These findings provide a rewarding avenue toward understanding of the influence of low temperature on battery performance, as well as the design of practical electrodes and batteries for low-temperature applications.
一般认为,低温环境通常会增加电解质粘度并阻碍电化学动力学,从而降低电池性能。然而,这一普遍观点虽然在某些情况下是正确的,但缺乏普遍性,尤其是在循环稳定性方面。在此背景下,钠-二硫化钼电池作为一个模型来阐明低温的影响。低温环境通过显著抑制二硫化钼的粉化和非晶化,有效降低了因大量物质穿梭至钠金属阳极而引发微短路的风险,从而避免了自放电导致的性能下降。在循环过程中,仅在低温下生成的NaMoS中间体有利于结构和电化学稳定性,以抵消固有的性能下降。低温下动力学的衰减促进了NaS的积累,类似于电极内的缓释剂,在长时间循环中稳定地提供容量。此外,抑制多硫化物的溶解和穿梭是低温下循环稳定性的关键因素。这些发现为理解低温对电池性能的影响以及设计用于低温应用的实用电极和电池提供了有益的途径。