scholarly journals Minimized lithium trapping by isovalent isomorphism for high initial Coulombic efficiency of silicon anodes

2019 ◽  
Vol 5 (11) ◽  
pp. eaax0651 ◽  
Author(s):  
Bin Zhu ◽  
Guoliang Liu ◽  
Guangxin Lv ◽  
Yu Mu ◽  
Yunlei Zhao ◽  
...  

Silicon demonstrates great potential as a next-generation lithium ion battery anode because of high capacity and elemental abundance. However, the issue of low initial Coulombic efficiency needs to be addressed to enable large-scale applications. There are mainly two mechanisms for this lithium loss in the first cycle: the formation of the solid electrolyte interphase and lithium trapping in the electrode. The former has been heavily investigated while the latter has been largely neglected. Here, through both theoretical calculation and experimental study, we demonstrate that by introducing Ge substitution in Si with fine compositional control, the energy barrier of lithium diffusion will be greatly reduced because of the lattice expansion. This effect of isovalent isomorphism significantly reduces the Li trapping by ~70% and improves the initial Coulombic efficiency to over 90%. We expect that various systems of battery materials can benefit from this mechanism for fine-tuning their electrochemical behaviors.

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Manisha Phadatare ◽  
Rohan Patil ◽  
Nicklas Blomquist ◽  
Sven Forsberg ◽  
Jonas Örtegren ◽  
...  

Abstract To increase the energy storage density of lithium-ion batteries, silicon anodes have been explored due to their high capacity. One of the main challenges for silicon anodes are large volume variations during the lithiation processes. Recently, several high-performance schemes have been demonstrated with increased life cycles utilizing nanomaterials such as nanoparticles, nanowires, and thin films. However, a method that allows the large-scale production of silicon anodes remains to be demonstrated. Herein, we address this question by suggesting new scalable nanomaterial-based anodes. Si nanoparticles were grown on nanographite flakes by aerogel fabrication route from Si powder and nanographite mixture using polyvinyl alcohol (PVA). This silicon-nanographite aerogel electrode has stable specific capacity even at high current rates and exhibit good cyclic stability. The specific capacity is 455 mAh g−1 for 200th cycles with a coulombic efficiency of 97% at a current density 100 mA g−1.


2016 ◽  
Vol 113 (27) ◽  
pp. 7408-7413 ◽  
Author(s):  
Jie Zhao ◽  
Hyun-Wook Lee ◽  
Jie Sun ◽  
Kai Yan ◽  
Yayuan Liu ◽  
...  

A common issue plaguing battery anodes is the large consumption of lithium in the initial cycle as a result of the formation of a solid electrolyte interphase followed by gradual loss in subsequent cycles. It presents a need for prelithiation to compensate for the loss. However, anode prelithiation faces the challenge of high chemical reactivity because of the low anode potential. Previous efforts have produced prelithiated Si nanoparticles with dry air stability, which cannot be stabilized under ambient air. Here, we developed a one-pot metallurgical process to synthesize LixSi/Li2O composites by using low-cost SiO or SiO2 as the starting material. The resulting composites consist of homogeneously dispersed LixSi nanodomains embedded in a highly crystalline Li2O matrix, providing the composite excellent stability even in ambient air with 40% relative humidity. The composites are readily mixed with various anode materials to achieve high first cycle Coulombic efficiency (CE) of >100% or serve as an excellent anode material by itself with stable cyclability and consistently high CEs (99.81% at the seventh cycle and ∼99.87% for subsequent cycles). Therefore, LixSi/Li2O composites achieved balanced reactivity and stability, promising a significant boost to lithium ion batteries.


2020 ◽  
Vol 10 (7) ◽  
pp. 2220
Author(s):  
Jie Deng ◽  
Yu Dai ◽  
Hui Dai ◽  
Luming Li

Given its high-capacity of multielectron (de-)lithiation, SnO2 is deemed as a competitive anode substance to tackle energy density restrictions of low-theoretical-capacity traditional graphite. However, its pragmatic adhibition seriously encounters poor initial coulombic efficiency from irreversible Li2O formation and drastic volume change during repeated charge/discharge. Here, an applicable gel pyrolysis methodology establishes a SnO2/Fe2O3 intercalated carbon monolith as superior anode materials for Li ion batteries to effectively surmount problems of SnO2. Its bulk-like, micron-sized, compact, and non-porous structures with low area surfaces (14.2 m2 g−1) obviously increase the tap density without compromising the transport kinetics, distinct from myriad hierarchically holey metal/carbon materials recorded till date. During the long-term Li+ insertion/extraction, the carbon matrix not only functions as a stress management framework to alleviate the stress intensification on surface layers, enabling the electrode to retain its morphological/mechanic integrity and yielding a steady solid electrolyte interphase film, but also imparts very robust connection to stop SnO2 from coarsening/losing electric contact, facilitating fast electrolyte infiltration and ion/electron transfer. Besides, the closely contacted and evenly distributed Fe2O3/SnO2 nanoparticles supply additional charge-transfer driving force, thanks to a built-in electric field. Benefiting from such virtues, the embedment of binary metal oxides in the dense carbons enhances initial Coulombic efficiency up to 67.3%, with an elevated reversible capacity of 726 mAh/g at 0.2 A/g, a high capacity retention of 84% after 100 cycles, a boosted rate capability between 0.2 and 3.2 A g−1, and a stable cycle life of 466 mAh/g over 200 cycles at 1 A g−1. Our scenario based upon this unique binary metal-in-carbon sandwich compact construction to achieve the stress regulation and the so-called synergistic effect between metals or metal oxides and carbons is economically effective and tractable enough to scale up the preparation and can be rifely employed to other oxide anodes for ameliorating their electrochemical properties.


2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Xiaoli Peng ◽  
Chong Wen ◽  
Qian Zhang ◽  
Hang Min ◽  
Yong Xiang ◽  
...  

AbstractCu2SnS3, as a modified material for high-capacity tin-based anodes, has great potential for lithium-ion battery applications. The solvothermal method is simple, convenient, cost-effective, and easy to scale up, and has thus been widely used for the preparation of nanocrystals. In this work, Cu2SnS3 nanoparticles were prepared by the solvothermal method. The effects of high-temperature annealing on the morphology, crystal structure, and electrochemical performance of a Cu2SnS3 nano-anode were studied. The experimental results indicate that high-temperature annealing improves the electrochemical performance of Cu2SnS3, resulting in higher initial coulombic efficiency and improved cycling and rate characteristics compared with those of the as-prepared sample.


RSC Advances ◽  
2019 ◽  
Vol 9 (60) ◽  
pp. 35045-35049
Author(s):  
Xu Chen ◽  
Jian Zhou ◽  
Jiarui Li ◽  
Haiyan Luo ◽  
Lin Mei ◽  
...  

High-performance lithium ion batteries are ideal energy storage devices for both grid-scale and large-scale applications.


Carbon ◽  
2013 ◽  
Vol 64 ◽  
pp. 158-169 ◽  
Author(s):  
Shuangqiang Chen ◽  
Peite Bao ◽  
Linda Xiao ◽  
Guoxiu Wang

2014 ◽  
Vol 2 (24) ◽  
pp. 9118-9125 ◽  
Author(s):  
Renzong Hu ◽  
Wei Sun ◽  
Yulong Chen ◽  
Meiqin Zeng ◽  
Min Zhu

Plasma-assisted milled Si/graphene nanocomposite anode delivers high capacity and good cycleability in half and full cells using a LiMn2O4 cathode.


Nanomaterials ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 18
Author(s):  
Tahar Azib ◽  
Claire Thaury ◽  
Fermin Cuevas ◽  
Eric Leroy ◽  
Christian Jordy ◽  
...  

Embedding silicon nanoparticles in an intermetallic matrix is a promising strategy to produce remarkable bulk anode materials for lithium-ion (Li-ion) batteries with low potential, high electrochemical capacity and good cycling stability. These composite materials can be synthetized at a large scale using mechanical milling. However, for Si-Ni3Sn4 composites, milling also induces a chemical reaction between the two components leading to the formation of free Sn and NiSi2, which is detrimental to the performance of the electrode. To prevent this reaction, a modification of the surface chemistry of the silicon has been undertaken. Si nanoparticles coated with a surface layer of either carbon or oxide were used instead of pure silicon. The influence of the coating on the composition, (micro)structure and electrochemical properties of Si-Ni3Sn4 composites is studied and compared with that of pure Si. Si coating strongly reduces the reaction between Si and Ni3Sn4 during milling. Moreover, contrary to pure silicon, Si-coated composites have a plate-like morphology in which the surface-modified silicon particles are surrounded by a nanostructured, Ni3Sn4-based matrix leading to smooth potential profiles during electrochemical cycling. The chemical homogeneity of the matrix is more uniform for carbon-coated than for oxygen-coated silicon. As a consequence, different electrochemical behaviors are obtained depending on the surface chemistry, with better lithiation properties for the carbon-covered silicon able to deliver over 500 mAh/g for at least 400 cycles.


2020 ◽  
Vol 5 (5) ◽  
pp. 895-903 ◽  
Author(s):  
Hehe Zhang ◽  
Chong Luo ◽  
Hanna He ◽  
Hong-Hui Wu ◽  
Li Zhang ◽  
...  

An anode of hard carbon spheres with both small size and a porous structure enables superior electrochemical performance of potassium-ion batteries.


2012 ◽  
Vol 463-464 ◽  
pp. 730-733 ◽  
Author(s):  
Lu Shi ◽  
Chao Lin Miao ◽  
Gai Rong Chen ◽  
Bin Xu ◽  
Shi Chen

The carbon materials prepared by PVDF carbonization at different temperatures have similar BET surface area and pores volume. The content of fluorine in the carbons decreased with the carbonization temperature from 1.46% (atm %) at 600°C to 0.18 %( atm %) at 1000°C. The first cycle specific capacity and the initial coulombic efficiency decreases with the decrease of fluorine content in the samples. The first cycle discharge capacity decreased from 982 mAh/ g at 600°C to 752 mAh/ g at 1000°C and the initial coulombic efficiency decreased from 31.8% at 600°C to 24% at 1000°C. It is believed that fluorine contained in the carbon materials has a positive effect to improve the electrochemical properties as anode materials for Li-ion batteries.


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