An apparatus was built to make accurate and precise in situ measurements of the volumes gas evolved Li-ion pouch cells during operation. With a thin film load cell accurately measuring weight submerged fluid, volume can be precisely monitored using Archimedes' Principle. Examples showing utility sensitivity device have been selected from made formation cycle (very first charge discharge) Li[Ni1/3Mn1/3Co1/3]O2/graphite (NMC) cells. Gas production occurs at very beginning but quickly stops for...

This preliminary study investigates initial gas formation in Li[Ni0.4Mn0.4Co0.2]O2 (NMC442) pouch cells with three different electrolytes: 3:7 ethylene carbonate : ethyl methyl (EC:EMC) w/ 1 M LiPF6 as the control, control + 2% prop-1-ene-1,3-sultone (PES) and vinylene (VC). In situ volume measurements reveal main features of evolution, an step, absorption, a second step at higher voltage. Gas chromatography-mass spectrometry is employed to identify gaseous compounds. work illustrates strong...

The capacity fade mechanisms of LiCoO2/Si-alloy:graphite pouch cells filled with a 1M LiPF6 EC:EMC:FEC (27:63:10) electrolyte were studied using galvanostatic cycling, electrochemical impedance spectroscopy on symmetric cells, gas-chromatography and differential voltage analysis. Analysis the gas generated during first cycle indicated that FEC reacts at negative electrode following 1-electron reduction pathway other pathways do not lead to formation gaseous products. An analysis showed is...

Single crystal Li[Ni 0.5 Mn 0.3 Co 0.2 ]O 2 //graphite (NMC532) pouch cells with only sufficient graphite for operation to 3.80 V (rather than ≥4.2 V) were cycled charging either 3.65 or facilitate comparison LiFePO 4 (LFP) on the grounds of similar maximum potential and negative electrode utilization. The NMC532 cells, when constructed be charged V, have an energy density that exceeds LFP a cycle-life greatly at 40 °C, 55 °C 70 °C. Excellent lifetime high temperature is demonstrated...

With a potential to deliver 60% greater energy density than conventional lithium-ion batteries, the simple design of anode-free lithium metal cells with liquid electrolytes has generated significant research interest. However, without excess lithium, short lifetime and safety concerns for cycling make development particularly challenging. Herein, we investigate effect four different positive electrode materials on performance cells—LiNi 0.5 Mn 0.3 Co 0.2 O 2 (NMC532), LiNi 0.8 0.1 (NMC811),...

The effectiveness of Prop-1-ene-1,3-sultone (PES) and Vinylene carbonate (VC) as electrolyte additives in Li(Ni1/3Mn1/3Co1/3)O2 (NMC)/graphite pouch cells was studied using situ measurements gas evolution, ultra high precision coulometry (UHPC), automated storage experiments electrochemical impedance spectroscopy (EIS). Gas show that containing PES produce less than 2% VC during formation much elevated temperature (60°C) at 4.2 V. UHPC cycling results have higher coulombic efficiency, lower...

Li-ion pouch cells were made to study the factors that influence gas evolution during formation (first charge). Electrode materials, electrolyte additives and temperature varied. Measurements using Archimedes' In Situ Gas Analyzer at Dalhousie University. When are charged high voltages (>4.2 V) there is evolution, presumed be from reactions on surface of positive electrode. This separate known happen lower voltage (<3.5 caused by negative Both evolutions characterized magnitude volume...

Unwanted redox shuttles can lead to self-discharge and inefficiency in lithium-ion cells. This study investigates the generation of a shuttle LFP/graphite NMC811/graphite pouch cells with common alkyl carbonate electrolyte. Visual inspection electrolyte extracted after formation at temperatures between 25 70 °C reveals strong discoloration. Such electrolytes intense red brown color show relatively large shuttling currents Al/Li coin Two weight percent vinylene is effective preventing as...

Vinylene carbonate (VC) and fluoroethylene (FEC) are compared as electrolyte additives for LiCoO2/graphite pouch cells using the ultra high precision charger (UHPC) at Dalhousie University, an automated storage system, electrochemical impedance spectroscopy (EIS) long term cycling. Both VC FEC useful that improve couloumbic efficiency (CE), reduce charge end point capacity slippage, long-term cycling self-discharge during to with control electrolyte. Increasing concentration of over 2%...

The use of LiPF 6 in Li-ion battery electrolytes provides sufficient stability, conductivity, and cost most applications. However, has also been known to cause degradation cells, primarily from its thermal decomposition or hydrolysis form acidic species. This work considers the imide salts lithium bis(fluorosulfonyl)imide (LiFSI) bis(trifluoromethanesulfonyl)imide (LiTFSI) as an alternative LiFePO 4 /Graphite cells. LiFSI LiTFSI over improved cycling performance both control electrolyte (no...

The effectiveness of ethylene sulfite (ES) and/or vinylene carbonate (VC) as electrolyte additives in Li(Ni1/3Mn1/3Co1/3)O2 (NMC)/graphite pouch cells was studied using situ measurements gas evolution, ultra high precision coulometry (UHPC), automated storage experiments and electrochemical impedance spectroscopy (EIS). Cells containing only ES produced large amounts during both formation cycling. UHPC cycling results showed that had lower coulombic efficiency, larger charge end point...

LiFePO 4 /graphite (LFP), Li[Ni 0.5 Mn 0.3 Co 0.2 ]O 2 (NMC3.8 V, balanced for 3.8 V cut-off), and 0.83 0.06 0.11 (Ni83, 4.06 cut-off) cells were tested at 85 °C. Three strategies used to improve cell lifetime all positive electrode materials 85°C. First, low voltage operation (&lt;4.0 V) was limit the parasitic reactions electrode. Second, LiFSI (lithium bis(trifluoromethanesulfonyl)imide) as electrolyte salt its superior thermal stability over LiPF 6 hexafluorophosphate). The avoids...

One of the main challenges in improving fast charging lithium-ion batteries is development suitable active materials for cathodes and anodes. Many suffer from unacceptable structural changes under high currents and/or low intrinsic conductivities. Experimental measurements are required to optimize these properties, but few techniques able spatially resolve ionic transport properties at small length scales. Here we demonstrate an atomic force microscope (AFM)-based technique measure local on...

High energy density cylindrical Li-ion cells are densely packed with active materials, inactive materials and electrolyte. Injected electrolyte generally fills all pore spaces in the electrodes separators of manufactured possibly some excess. When such charged, overall volume electrode increases therefore is pushed under hydraulic pressure to outside winding at ends can also into hollow core winding. During discharge this reenters as particles contract. Therefore, moment inertia cell about...

Physical mixtures of LiMn 2 O 4 (LMO) and NMC active cathode materials is a well-known strategy in commercial batteries to achieve better cycling storage performance than cells with pure LMO cathode. In this work, we demonstrated similar synergic effect LiFePO (LFP)/NMC640 material blends. Blending LFP NMC640 the weight ratio 90% 10% lead improvements compared alone. A clear linear coordination between capacity loss iron deposition on graphite anode was observed these blended cells. This...

Predicting the end-of-life (EOL) of lithium-ion batteries across different manufacturers presents significant challenges due to variations in electrode materials, manufacturing processes, cell formats, and a lack generally available data. Methods that construct features solely on voltage-capacity profile data typically fail generalize chemistries. This study introduces methodology combines traditional with Direct Current Internal Resistance (DCIR) measurements, enabling more accurate...

This work involves improving the lifetime of lithium-ion cells during high voltage cycling using electrolyte additives. Three generations additives were investigated and screened in NMC442/graphite pouch a 24 h voltage-hold protocol at 40 °C to accelerate oxidative reactions occurring 4.4 V. Once promising combinations identified, they then tested cobalt-free NMC640/graphite for long-term upper cutoff voltages 4.3, 4.4, 4.5 V temperatures 20, 40, 55 °C. Degradation mechanisms probed dV/dQ...

Li[Ni 0.5 Mn 0.3 Co 0.2 ]O 2 /graphite pouch cells were cycled using protocols that included 24 h spent at high voltage (≥ 4.3 V) under constant or open circuit conditions to accelerate failure. Compared traditional cycling, failure was reached up 3.5 times faster. When this protocol applied containing low LiPF 6 concentrations (≤ 0.4 M) achieved 17.5 faster than cycling with normal concentrations. This represents a time improvement on the order of years and therefore can be used as...

Lithium-ion batteries will contribute to the energy storage needs that enable widespread implementation of renewable alternatives fossil fuels. Here role cell lifetime in achieving sufficient battery deployment satisfy these is discussed context manufacturing limitations and necessity developing cells with lifetimes beyond those found contemporary cells. A design, usage scheme reliant on this demonstrates vastly improved capability presented, including traditional definitions end-of-life....

The electrolyte additive lithium difluorophosphate improves the lifetime of lithium-ion cells. This work presents synthesis and evaluation alternative salt additives. Ammonium is readily prepared via a solid-state, benchtop reaction ammonium fluoride phosphorus pentoxide that requires only gentle heating to initiate. best yield sodium (NaFO) in present study was obtained by reacting difluorophosphoric acid carbonate 1,2-diemethoxyethane over 3 Å molecular sieves. Tetramethylammonium from...

In search for new classes of additives high voltage NMC/graphite lithium-ion cells, the precursor additive bis(trimethylsilyl) malonate (bTMSM) is shown to be activated via a spontaneous reaction with LiPF 6 and LiBF 4 salts in carbonate-based electrolyte form lithium tetrafluoro(malonato)phosphate (LiTFMP), difluoro(malonato)borate (LiDFMB), respectively. The schemes rates were studied NMR spectroscopy GCMS. effects LiTFMP LiDFMB on electrochemical performance then examined up 4.5 V Li[Ni...