Advanced Nano-Composite Lithium-Metal-Oxide Electrodes for High Energy Lithium-Ion Batteries Sun– Ho Kang Chemical Sciences and Engineering Division Argonne National Laboratory, Argonne, IL 60439 The 7 th US-Korea Forum on Nanotechnology: Nanomaterials and Systems for Nano Energy Seoul, Korea, April 5-6, 2010
Diverse Applications of Li-ion Batteries e.g.,SoCalEdison-A123 e g SoCalEdison A123 32 MWh LIB Hearing devices Military Applications Neuro-stimulator Consumer Electronics Pacemaker Li-ion Batteries Li i B tt i Insulin pump as power sources Smart Grid Bone growth stimulator (Utility-scale energy storage) Medical Devices Beagle 2 Miscellaneous Spaceships and Satellites (power tools, backup power, etc.) Transportation e.g.,HEV, PHEV, EV, E-Bike
Why Li-ion Batteries? 400 400 Secondary batteries sales (US) aller aller 350 350 / l) / l) sma sma Density (Wh/ Density (Wh/ Lithium Batteries Lithium Batteries (LIB, LPB…) (LIB, LPB…) 300 300 250 250 ric Energy D ric Energy D 200 200 Ni-MH Ni-MH 150 150 Ni Zn Ni-Zn Ni Zn Ni-Zn Volumet Volumet Ni-Cd Ni-Cd 100 100 Lead-Acid Lead-Acid lighter lighter 50 50 0 0 0 40 80 120 160 200 0 40 80 120 160 200 Gravimetric Energy Density (Wh/ kg) Gravimetric Energy Density (Wh/ kg) � Li ‐ ion battery is the battery chemistry of choice for future generations of energy storage systems for portable electronics, power tools, and electric vehicles. LIB storage systems for portable electronics, power tools, and electric vehicles. LIB is also one of the candidates for utility ‐ scale electric energy storage systems.
LIB as Energy/Power Source for Transportation � Plug ‐ in Hybrid Electric Vehicles (PHEV) – A hybrid vehicle with batteries that can be recharged by connecting A h b id hi l i h b i h b h d b i a plug to an electric power source (or by ICE, if necessary): all electric range of 10+ miles (current target: 40+ miles) g ( g ) – Impact on Energy, Economy, and Environmental Issues • About half the gasoline consumed in the U.S. is consumed in the first 20 miles of daily travel of an automobile. • Therefore, PHEV can significantly reduce foreign oil dependence as well as toxic and greenhouse gas emission • President Obama’s speech to congress (24 Feb 2009): “We know the country that harnesses the power of clean, renewable energy will lead the 21st century. … New plug ‐ in hybrids roll off our assembly lines, but they will run on batteries made in Korea.” • Significant, nation ‐ wide investment is being made by US (federal and state) government and commercial sectors for R&D activity as well as for establishing manufacturing industry (job creation)
DOE Targets for Energy Storage Systems for HEVs, PHEVs, and EVs and EVs DOE Energy Storage Goals HEV(2010) PHEV(2015) EV(2020) Characteristics h Unit Equivalent Electric Range miles N/A 10 ‐ 40 200 ‐ 300 Discharge Pulse Power kW 25 ‐ 40 for 10 sec 38 ‐ 50 80 Regen Pulse Power (10 seconds) l ( d ) k kW 20 ‐ 25 25 ‐ 30 40 Recharge Rate kW N/A 1.4 ‐ 2.8 5 ‐ 10 Cold Cranking Power @ ‐ 30 ºC (2 seconds) kW 5 ‐ 7 7 N/A Available Energy Available Energy kWh kWh 0.3 ‐ 0.5 0.3 0.5 3.5 ‐ 11.6 3.5 11.6 30 ‐ 40 30 40 Calendar Life Year 15 10+ 10 Cycle Life Cycles 300k, shallow 3,000 ‐ 5,000, deep 750, deep discharge discharge Maximum System Weight kg 40 ‐ 60 60 ‐ 120 300 Maximum System Volume l 32 ‐ 45 40 ‐ 80 133 Operating Temperature Range ºC ‐ 30 to 52 ‐ 30 to 52 ‐ 40 to 85 Selling Price @ 100k units/year Selling Price @ 100k units/year $ $ 500 800 500 ‐ 800 1 700 ‐ 3 400 1,700 3,400 4 000 4,000 � No commercially available chemistries (cathode, anode, electrolyte, etc.) meet the DOE targets for PHEVs and EVs with 40+ electric range targets for PHEVs and EVs with 40+ electric range. - Key issues: Energy, Life, Safety, and Cost
Approach � Multi ‐ institution team assembled to design synthesize characterize and model Multi institution team assembled to design, synthesize, characterize, and model oxide structures for next ‐ generation electrode materials Vehicle Technology Vehicle Technology DOE Materials design and synthesis and synthesis (CSE, Argonne) Electrochemistry Structure Models (CSE, Argonne) (CSE, Argonne) X-ray Absorption Electron Solid-State NMR Spectroscopy Microscopy (Stony Brook) (APS, Argonne) ( , g ) (UIUC) ( ) (Brookhaven) (MIT)
What happens in a Li-ion cell? e - charge charger e - discharge LiCoO 2 Graphite C Cu curr ollector rent col Discharging Discharging rent co Ch Charging i Li + + e - � Li Li � Li + + e - electrolyte Supplies Energy Requires Energy Al curr llector separator (+) Process reversibility (-) should be ~100% for good cycle life
Active material in cathode is the source of lithium ions LiMPO 4 LiMO 2 LiMn 2 O 4 (M=Fe, Ni, Co) (M=Ni, Co, Mn, Li) 1D 1D 2D 2D 3D 3D Pros : Pros : Pros : • Excellent safety • High theoretical capacity (~ • Fast Li motion through 3D 280 mAh/g) Li channel • Cost advantage (Fe) • Low cost (Mn-based) Cons : Cons : Cons : Cons : • Structural destabilization at St t l d t bili ti t • Poor conductivity high SOC • Low theoretical capacity ( • Low theoretical capacity • Highly oxidizing/unstable ~150 mAh/g) (~170 mAh/g) Ni 4+ and Co 4+ poor • Capacity fading (Mn y g ( thermal safety thermal safety dissolution, Jahn-Teller distortion)
Limitations of layered lithium metal oxides Li(Li 1/3 Mn 2/3 )O 2 ( ≡ Li 2 MnO 3 ) LiMO 2 (M=Ni,Co,Mn) TM plane TM plane � Similar structure to LiMO 2 � For last two decades, layered LiMO 2 (mostly LiCoO 2 ) has been the positive electrode • One-third of M is replaced with Li chemistry of choice for the LIBs for portable y p • Strong ordering between Li + and Mn 4+ St d i b t Li + d M 4+ electronics. � Electrochemistry � Limitations • at <4.4 V vs. Li + /Li, Li 2 MnO 3 is electrochemically inactive l t h i ll i ti • High cost of Co and Ni Hi h t f C d Ni • Low practical conductivity (~150 mAh/g vs. ~280 • At >4.4 V vs. Li + /Li, lithium can be extracted together with oxygen: theoretical capacity of LiCoO 2 ) due to the structural instability at low Li content (Li/M<0.5) Li 2 Mn 4+ O 3 → Li 2 O + Mn 4+ O 2 (460 mAh/g) Li 2 Mn O 3 → Li 2 O + Mn O 2 (460 mAh/g) • Conversion to spinel during cycling (LiMnO 2 ) • However, the activated electrode tends to • Highly unstable and oxidizing Ni 4+ and Co 4+ at convert to spinel with cycling (same issue as charged state: thermal safety issues LiMnO 2 ) Not a good electrode material for high energy Not a good electrode material for high energy Li- ion batteries with intrinsic thermal safety! Li-ion batteries with longevity!
Nano-composite among Li 2 MnO 3 , LiMO 2 , and LiM’ 2 O 4 � A unique approach of integrating lithium metal oxides with structural compatibility in nano ‐ composite structures: (1) ‘layered ‐ layered’ electrodes with layered Li 2 MnO 3 and LiMO 2 components (1) layered layered electrodes with layered Li 2 MnO 3 and LiMO 2 components (2) ‘layered ‐ layered ‐ spinel’ electrodes comprised of layered Li 2 MnO 3 , layered LiMO 2 and spinel LiM’ 2 O 4 components. � Motivation Motivation – Enhancing structural stability: integration of Li 2 MnO 3 as a structural stabilizing agent in LiMO 2 matrix to prevent structure collapse of the layered structure at low Li content – Increasing capacity: activation of Li 2 MnO 3 at high voltages Increasing capacity: activation of Li 2 MnO 3 at high voltages An example of layered-layered nano-composite structure LiMO 2 region Li 2 MnO 3 region LiMO 2 region Li 2 MnO 3 region
Structural compatibility of Li 2 MnO 3 and LiMO 2 : Li 1.2 Ni 0.2 Mn 0.6 O 2 XRD pattern Electron diffraction 3) (003 ary unit) (104) ty (arbitra 020) C2/m m 10) C2/m 1) C2/m 01) 10) 8) (0 (10 (018 (11 (012) ) (1 Intensi (11- (107) (006) (015) (113) Li 2 MnO 3 10 20 30 40 50 60 70 80 2 θ � Mostly LiMO 2 -like (rhombohedral, R-3m) feature with Li 2 MnO 3 - like (monoclinic, C2/m) characters (cation ordering peaks and diffuse streaks) � Li 1.2 Ni 0.2 Mn 0.6 O 2 ≡ 0.5Li 2 MnO 3 • 0.5LiNi 0.5 Mn 0.5 O 2
Structural compatibility of Li 2 MnO 3 , LiMO 2 , and LiM’ 2 O 4 : Li Li 0.96 Ni 0.2 Mn 0.6 O y (y~1.88) Ni Mn O (y~1 88) X-ray diffraction patterns LiMO 2 Li 0.96 Ni 0.2 Mn 06 O y unit) (layered) + + h h arbitrary calcined at 900 ° C co Li 2 MnO 3 h S h S S S (layered with cation (layered with cation ensity (a 800 ° C ordering) + Inte 700 ° C 700 C LiM’ 2 O 4 (spinel) 10 10 20 20 30 30 40 40 50 50 60 60 70 70 80 80 h : X-ray sample holder 2 θ CuK α co , cation ordering; s , spinel � Three ‐ component integrated structure Three component integrated structure � Li 0.96 Ni 0.2 Mn 0.6 O y ≡ 0.3LiNi 0.5 Mn 1.5 O 4 •0.7Li 2 MnO 3 •0.7LiMO 2 (M=Ni 0.5 Mn 0.5 )
Nano-composite feature of Li 0.96 Ni 0.2 Mn 0.6 O y : 0.3LiNi 0 5 Mn 1 5 O 4 • 0.7Li 2 MnO 3 • 0.7LiMO 2 (M=Ni 0 5 Mn 0 5 ) 2 ( 0.5 ) 0.5 1.5 4 2 3 0.5 HR TEM image This HR TEM image demonstrates the structural integration of spinel (Fd 3m) This HR TEM image demonstrates the structural integration of spinel (Fd ‐ 3m) and layered (C2/m).
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