Building better lithium-sulfur batteries: from LiNO 3 to solid oxide catalyst

Transcription

1 Supplementry Informtion Building etter lithium-sulfur tteries: from LiN to solid oxide ctlyst Ning Ding, Ln Zhou, Chngwei Zhou, Dongsheng Geng, Jin Yng, Sheu Wei Chien, Zholin Liu, Mn-Fi Ng, Aishui Yu, T. S. Andy Hor, Michel B. Sullivn nd Yun Zong Preprtion of trnsition metl oxide-grphite composites Most of trnsition metl oxide-grphite composites (:9, w/w) were prepred vi therml decomposition of nitrte t high tempertures. Metl nitrte ws dissolved in the ethnol-wter solution (:, v/v), nd then grphite (KS6) ws dded nd dried under vigorous stirring t 00 C. For TiO, V nd MoO, the precursors were titnium methoxide (Ti(OCH ) ), mmonium metvndte (NH V ) nd molydic cid (Mo H O), respectively. To fully dissolve Mo H O, mmonium hydroxide solution ws grdully dded until the solution chnged from muddy to cler. The s-prepred powders were collected nd finlly decomposed t 600 C for h under Ar tmosphere. The pplied low decomposition temperture prevents the crotherml rection (usully ove 800 C) etween trnsition metl oxide nd grphite. However, t 600 C only ntse-tio ws otined nd the high-temperture stle rutile- TiO ws chieved y heting Ti(OCH ) /grphite composite to 900 C for h. The impregntion of RuO ws vi co-precipittion method. Ruthenium chloride (RuCl H O) ws firstly dissolved in wter nd stirred for 0. h. Then grphite ws dded into the solution nd stirred for 0. h t room temperture. Susequently, sodium hydroxide solution (.0 M) ws slowly dded to djust the ph vlue to 7. The suspension ws continuously stirred for h for ging, then filtered nd wshed with deionized wter severl times to remove sodium chloride residul, nd finlly heted t 0 C for h.

2 ICE (%) Sulfur loding density (mg cm - ) Supplementry Figure S: Correltion etween initil coulomic efficiency (ICE) nd sulfur loding density (SLD) of Li-S cells cycled in 80 µl LiN -free electrolyte. If SLD < 0.8 mg cm -, ICE decresed lmost linerly with the increse of SLD; wheres for SLD >. mg cm -, the increse of SLD led to slightly higher ICE. Interestingly, with 0.8 < SLD <. mg cm - ICE flls in the rnge of 6±%. This uffer-like ehvior llows for the doption of SLD ~ 0.9±0. mg cm - t which ICE is inert to minor devition of SLD, fcilitting study on dditionl fctors tht ffect ICE.

3 c d Supplementry Figure S: Glvnosttic dischrge-chrge voltge profiles of grphite/sulfur composite cycled in LiN -free electrolyte with different volumes: () 80 µl (ICE: 66.%), () 60 µl (ICE: 79.%), (c) 0 µl (ICE: 86.%) nd (d) 0 µl (ICE: 99.%). A Li-S cell with 80 μl electrolyte gve n extremely long chrge voltge plteu t. V with n ICE of only 66.%, indicting severe redox shuttle effect. In contrst, with reduced volume of electrolyte (e.g. 0 μl) similr cell exhiited significntly improved cycling performnce with ICE s high s 99.%, showing effective suppression of redox shuttles. The higher ICE t smller volume of electrolyte ws likely due to the incresed viscosity t higher LiPSs concentrtion in electrolyte tht slowed down the diffusion of LiPSs from cthode to node.

4 c Chrge Time (min) CE: 7.6% d CE: 8.0% CE: 9.% CE: 00.% Supplementry Figure S: Glvnosttic intermittent titrtion nlysis mesured y 0 min of glvnosttic chrge/dischrge (0. ma), followed y 0 mins of relxtion time. Cells were cycled in LiN -free electrolyte. () Glvnosttic intermittent titrtion curve vs. cpcity nd the inset of glvnosttic intermittent titrtion curve vs. time (two steps mrked on chrging). Glvnosttic dischrge-chrge voltge profiles () efore nd (c) fter GITT mesurement. The relxtion process in GITT test clerly leds to n extremely low CE (7.6%). (d) Glvnosttic intermittent titrtion curve vs. cpcity of the cell with LiN -contined electrolyte. The ddition of LiN cn significntly improve CE even in GITT test (still round 00%). Electrolyte volume: 0 µl.

5 Specific Cpcity (mah g - cron ) V Specific Cpcity (mah g - cron ) Supplementry Figure S: Glvnosttic dischrge-chrge voltge profiles of grphite cycled in () LiN -free electrolyte nd ().0 wt% LiN contined electrolyte. The reduction of LiN on grphite strts off t the voltge of V nd the reduction product is irreversile in the following cycles.

6 Supplementry Figure S: Glvnosttic dischrge-chrge voltge profiles of grphite/sulfur composite cycled in LiN -contined electrolyte with different low cut-off voltge. () V nd ().0 V. The cell with higher cut-off voltge exhiits etter cycling performnce.

7 0 0 Time (hr) Supplementry Figure S6: Glvnosttic dischrge-chrge voltge profiles of grphite/sulfur composite with cycled in.0 wt% NN -contined electrolyte. The introduction of NN cn lso suppress the shuttle phenomenon.

8 0 0 0 Resistnce ( ) Resistnce ( ) R s R SEI R ct 0 R s R SEI R ct -Z'' ( ) 0 CPE CPE R s :.0 Ω R SEI : 8. Ω R ct :. Ω -Z'' ( ) 0 CPE CPE R s :. Ω R SEI : 7. Ω R ct :. Ω 0 0 c Z' ( ) d Z' ( ) R SEI 0 R SEI 0 0 R ct 0 R ct Storge Time (dy) Storge Time (dy) Supplementry Figure S7: Nyquist plots of the cells with () LiN -free electrolyte nd ().0 wt% of LiN stored t room temperture for dys. The inset shows the corresponding equivlent circuit model. Vrition of R SEI /R ct vs. storge time for the cells with (c) LiN -free electrolyte nd (d).0 wt% LiN stored t room temperture. Compred with the cell without LiN, fster increse of R SEI is oserved for the cell with LiN due to the progressive rection etween LiN nd Li node, wheres R ct remins constnt vlue in storge, indicting low self-dischrge rte.

9 ...0 dditive free wt% LiN (low cut-off voltge: V) wt% LiN (low cut-off voltge:.0 V) Storge Time (dy) Supplementry Figure S8: Voltge chnge of the cells with/without LiN stored t room temperture. A similr voltge chnge of the cells with low cut-off voltges of nd.0 V excludes the influence of Li x NO y pssivtion lyer on cthode on self-dischrge rte.

10 ntse-tio rutile-tio c ICE: 88.8% V d ICE: 8.0% Cr e MnO ICE: 8.8% f ICE: 8.6% Fe O g ICE:.6% CoO h ICE: 9.% ZnO ICE: 77.6% 00 ICE: 86.% Supplementry Figure S9: Initil dischrge-chrge voltge profiles of Li-S tteries cycled in LiN - free electrolyte with the trnsition metl oxide (in period )-grphite composite (:9, w/w) s the sustrte. () ntse-tio, () rutile-tio, (c) V, (d) Cr, (e) MnO, (f) Fe O, (g) CoO nd (h) ZnO. The electrode consists of 0 wt% of sulfur with loding density is 0.9 mg cm -. Electrolyte volume: 80 µl. Applied current: 0. ma. With sulfur loding density of 0.9 mg cm -, re grphite cn only deliver n ICE of 6% (Figure S). Among the studied trnsition metl oxides in period, the introduction of V, MnO nd Fe O induces to lower ICE vlue, wheres TiO (oth phses) nd ZnO clerly hve positive effect, with n ICE vlue of ove 8%. The influence of ntse TiO on CE is lso pproved y Amine et l.

11 ZrO MoO c ICE: 77.6% RuO d ICE: 79.9% CdO ICE: 9.% ICE:.% Supplementry Figure S0: Initil dischrge-chrge voltge profiles of Li-S tteries cycled in LiN - free electrolyte with the trnsition metl oxide (in period )-grphite composite (:9, w/w) s the sustrte. () ZrO, () MoO, (c) RuO nd (d) CdO. The electrode consists of 0 wt% of sulfur with loding density is 0.9 mg cm -. Electrolyte volume: 80 µl. Applied current: 0. ma.

12 L CeO c ICE: 78.6% Gd d ICE: 8.9% T e ICE: 8.9% Y f ICE: 87.7% Lu ICE: 69.8% 00 ICE: 86.% Supplementry Figure S: Initil dischrge-chrge voltge profiles of Li-S tteries cycled in LiN - free electrolyte with the rre erth oxides in the lnthnide series)-grphite composite (:9, w/w) s the sustrte. () L, () CeO, (c) Gd, (d) T, (e) Y nd (f) Lu. The electrode consists of 0 wt% of sulfur with loding density is 0.9 mg cm -. Electrolyte volume: 80 µl. Applied current: 0. ma. All the studied rre erth oxides cn deliver higher ICE thn re grphite (6%), ut re not superior to RuO. The introduction of RuO leds to the highest ICE (9.%) mong ll 8 trnsition metl oxides.

13 c TiO -Antse PDF#-7 TiO -Rutile PDF#6-09 V PDF#9-077 d e f Cr PDF#8-79 MnO PDF#07-00 Fe O PDF#6-07 CoO PDF#-00 g h i ZnO PDF#6- ZrO PDF#6-0 ZrO PDF#9-6 MoO PDF#-067 j k l RuO PDF#-07 CdO PDF# wt% RuO L PDF#0-79 wt% RuO m n o CeO PDF#-00 Gd PDF#6-8 T PDF#6-80 p q r Y PDF#-06 Lu PDF#-078 Supplementry Figure S: XRD ptterns of the s-prepred trnsition metl oxide-grphite composites. () pure ntse TiO, () rutile TiO with trce of ntse TiO, (c) morphous V (the composition is determined y ref. ), (d) Cr (spce group: R-c), (e) MnO (spce group: Fm-m), (f) Fe O (spce group: Fd-m), (g) CoO (spce group: Fm-m), (h) ZnO (spce group: P6 mc), (i) mixture of monoclinic ZrO (spce group: P /c) nd cuic ZrO (spce group: Fm-m), (j) MoO (spce group: P /n), (k) RuO (spce group: P /mnm), (l) CdO (spce group: Fm-m), (m) L (spce group: P-m), (n) CeO (spce group: Fm-m), (o) Gd (spce group: I-), (p) T (spce group: I-), (q) Y (spce group: I-) nd (r) Lu (spce group: I-). The peks mrked with n sterisk rise from the impurity of KS6.

14 Weight % Quntity Adsored (cm g - ) Grphite MWCNTs Reltive Pressure (P/P 0 ) MWCNTs RuO -MWCNTs Temperture ( o C) Supplementry Figure S: () Adsorption desorption isotherms of grphite (BET surfce re = 7.8 m g nd MWCNT (BET surfce re = 6. m g ). () TGA curves of pure MWCNTs nd RuO -MWCNTs composite.

15 Specific Cpcity (mah g - cron ) 9 V.6 V Specific Cpcity (mah g - cron ) Supplementry Figure S: Glvnosttic chrge-dischrge voltge profiles of MWCNTs cycled in () LiN -free electrolyte nd () wt% LiN -conting electrolyte. In the first cycle, the reduction of LiN results in two dditionl voltge plteus t 8 nd V.

16 0 th st Supplementry Figure S: Glvnosttic chrge-dischrge voltge profiles of MWCNTs cycled in the electrolyte with wt% LiN. Cut-off voltge:.0 ~.8 V.

17 Coulomic Efficiency % Cell A 0 Cell B Cycle Numer Supplementry Figure S6: Cycling performnce of two grphite-sulfur electrodes (Cell A nd Cell B) in LiN -contined electrolyte t the cycling rte of C/.. References. Xu, R.; Li, J. C. M.; Lu, J.; Amine, K.; Belhrouk, I. J. Mter. Chem. A 0,, 70.. Stnder, F.; Vn Vuuren, C. P. J. Thermochim. Act 990, 6, 8.