Tin Networked Electrode Providing Enhanced Volumetric Capacity and Pressureless Operation for All-Solid-State Li-Ion Batteries

Abstract

Pure tin (Sn) metal nano-powder is investigated as a high capacity negative electrode for rechargeable all-solid-state Li-ion batteries. Sn is used to form a fully dense network intertwining with solid electrolyte negating necessary conductive additive. Galvanostatic cycling of the Sn composite electrode delivers a reversible capacity 800 mAh g −1 of Sn with a constant coulombic efficiency over 99.2%. We report on the effect of pressure and rate upon the delithiation mechanics, drawing correlations between Sn volume increase factors and stress accumulation over the course of Sn-Li phase transformations. Due to the fabricated electrode microstructure, we are able to operate the cell at ambient pressure conditions -the next step toward commercialization of the solid-state battery. We believe that this initial work provides new opportunities to study the electrochemical expansion of Sn with the inclusion of rigid electrolyte particles. In 1997, Fuji announced a tin (Sn)-based amorphous composite oxide material for commercial Li-ion batteries.1 Ensuing anode deployments include the Sony developed Sn-based compound (Sn-Co-C) in 2005.2 Although these were the first commercial deployments of Sn-based anodes, Sn has been extensively studied for decades as a candidate in rechargeable Li-ion batteries because of its substantial lithium storage capabilities and quicker charging times.3 Despite the theoretical capacity of Sn being lower than the currently spotlighted silicon (Si) anode, Sn has exceptionally appealing features: high gravimetric and volumetric capacity (959 mAh g −1 and 2,476 mAh mL −1 for 4.25 Li-ions), 4 excellent electrical conductivity (9.17 × 10 6 S m −1 ), and room temperature Li-ion diffusivity (5.9 × 10 −7 cm 2 s −1 of Li 4.4 Sn). 5 The commercialized Sn-Co-C anode by Sony provides a significant capacity advantage over the currently utilized graphite anode material (372 mAh g −1 ). However, wide use of the Sn-Co-C anode has been limited due to the high cost and environmental concerns about cobalt. Iron and nickel have been introduced as replacements for cobalt forming amorphous Sn-Fe and Sn-Ni with similar electrochemical properties to the Sn-Co alloy.6-10 Despite the low cost and high capacity of the Sn-Fe and Sn-Ni anodes, poor cycling stability and coulombic efficiency (CE) hinder their practical use in Li-ion batteries. These drawbacks mainly result from the notorious volume change of Sn (∼255% when 4.25 Li-ion inserted), 4,11 leading to a loss of electric contact, pulverization, and cracking.12 Therefore, controlling the microstructure of the expandable active material during lithiation/delithiation processes is a key point to realize a high energy-dense Li-ion battery using Sn-based anode materials.Recently, Molina Piper et al. reported the effect of compressive stress on the electrochemical performance of a Si anode in an allsolid-state Li-ion cell, which similarly suffers from pulverization due to immense volume changes.13 By applying external compressive stress to the silicon/solid-state elec...

On the Additive Microstructure in Composite Cathodes and Alumina-Coated Carbon Microwires for Improved All-Solid-State Batteries

“…In general, poor thermodynamic stability of the SE, , chemo-mechanical coupling, , and interface kinetics are the remaining major challenges. At the anode, the reduction of thiophosphate SEs by lithium metal occurs and a solid electrolyte interphase (SEI) forms. , In the cathode composite, side reactions take place at three locations.…”

Thin and Flexible Solid Electrolyte Membranes with Ultrahigh Thermal Stability Derived from Solution-Processable Li Argyrodites for All-Solid-State Li-Ion Batteries

“…53,63,64 ■ ASSOCIATED CONTENT * sı Supporting InformationThe Supporting Information is available free of charge at https://pubs.acs.org/doi/10.1021/acsenergylett.0c00251. Experimental methods, synthetic scheme of PI NWs, FTIR spectrum for PI, activation energy, unit cell volume, and CV results for solution-processed Li 6 PS 5 Cl 1−x Br x heat-treated at 400 °C, photograph of PI−LPSClBr during a bending test, photograph of the LPSClBr pellet, Nyquist plots of SE membranes and the equivalent circuit model, photographs of PEI and PEI− LPSClBr, result of DC polarization test, cross-sectional SEM images of NCM/PI−LPSClBr/LTO all-solid-state full cells, Nyquist plots for NCM/PI−LPSClBr/LTO allsolid-state cells, voltage profiles of NCM/PI−LPSClBr/ LTO and NCM/(LPSClBr pellet)/LTO all-solid-state full cells, high-temperature exposure test for the OPC SE membrane, and rate capability of LPSClBr-infiltrated LCO/(PI NWs)/LTO ASLB full cells (PDF) Movie clip of PI−LPSClBr during a bending test (MP4) School of Energy and Chemical Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, South Korea; orcid.org/0000-0001-7153-0517; Email: syleek@unist.ac.kr Yoon Seok Jung − Department of Energy Engineering, Hanyang University, Seoul 04763, South Korea; orcid.org/0000-0003-0357-9508; Email: yoonsjung@hanyang.ac.kr…”

“…First, further enhancement of Li + conductivity for solution-processable SEs should be researched by elaborating on the composition and/or synthetic protocols. ,,, Second, development of composite electrodes that withstand high-heat-treatment temperature conditions (i.e., thermally stable binders, binder-less electrodes, and interfacial engineering to suppress the reaction between electrode active materials and SEs) should be pursued. Third, evaluation and engineering of SE membranes to make them compatible with alternative high-capacity anodes, including Li metal, Si, and Sn, are required. ,, …”

Electrochemical Properties of Multilayered Sn/TiNi Shape-Memory-Alloy Thin-Film Electrodes for High-Performance Anodes in Li-Ion Batteries

“…Current commercial graphite anodes have an unsuitably low theoretical capacity of 372 mAh/g [ 3 , 4 ]. Therefore, other anode materials with higher capacity such as Si, Sn, SnO 2 , and Li have attracted interest [ 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 ].…”

“…However, as illustrated in Figure 1 a, the lager volume expansion and contraction of Sn particles during lithiation–delithiation causes pulverization and cracking, and thus, fading capacity. To overcome this problem and improve the cycle life, volume change and internal stress need to be suppressed or alleviated [ 7 , 8 , 9 ].…”