Emerging trends in sustainable battery chemistries

Sustainability of critical metals supply is a matter of utmost importance for both battery researchers and manufacturers.Direct recycling is a promising emerging strategy to recover critical metals such as lithium, cobalt, and nickel and all other components in a cost-effective and environmentally friendly manner.Designs of current and next-generation batteries can be improved from the materials to the cell and module level to facilitate recyclability and improve profitability.To meet renewable energy generation and storage goals, alternative battery paradigms are needed to address long-term critical metal sustainability. With the rapid growth in demand for lithium-ion batteries (LIBs) in our increasingly electrified economy, there is an urgent need for a sustainable supply chain enabled by efficient recycling of critical metals. While significant improvements in recycling technologies have been achieved, they still face challenges in the recovery of all of the LIB components. In this review, we discuss the importance of recovering critical materials and how battery designs can be improved to facilitate recyclability. Recycling-friendly designs of next-generation all-solid-state and sodium-ion batteries are also discussed, in an effort to ensure sustainability before commercialization. Emerging trends in renewable energy and its corresponding scale of battery storage needed are introduced, with new perspectives on alternative battery paradigms to address long-term critical metal sustainability. With the rapid growth in demand for lithium-ion batteries (LIBs) in our increasingly electrified economy, there is an urgent need for a sustainable supply chain enabled by efficient recycling of critical metals. While significant improvements in recycling technologies have been achieved, they still face challenges in the recovery of all of the LIB components. In this review, we discuss the importance of recovering critical materials and how battery designs can be improved to facilitate recyclability. Recycling-friendly designs of next-generation all-solid-state and sodium-ion batteries are also discussed, in an effort to ensure sustainability before commercialization. Emerging trends in renewable energy and its corresponding scale of battery storage needed are introduced, with new perspectives on alternative battery paradigms to address long-term critical metal sustainability. The onset of the 21st century saw an expeditious growth in adoption rates for LIBs, especially in the consumer electronics and electric vehicle (EV) markets [1.Li L. et al.The recycling of spent lithium-ion batteries: a review of current processes and technologies.Electrochem. Energy Rev. 2018; 1: 461-482Crossref Scopus (100) Google Scholar,2.Lv W. et al.A critical review and analysis on the recycling of spent lithium-ion batteries.ACS Sustain. Chem. Eng. 2018; 6: 1504-1521Crossref Scopus (417) Google Scholar]. Coupled with rising rates of renewable energy generation, the tumbling prices of LIBs (>US$900/kWh in 2011 versus >US$150/kWh in 2020i) have also driven increased electrification of our lives. Despite the promising trends in carbon footprint reductions and reduced reliance on fossil fuels, developments in battery waste management and sustainable recycling are still lacking. This presents us with a growing and dangerous battery waste accumulation problem [3.Kong L. et al.Li-ion battery fire hazards and safety strategies.Energies. 2018; 11: 2191Crossref Scopus (108) Google Scholar], especially as increasing number of EVs approach their end of life (EOL) and exit the roads. Unlike regular consumer waste (e.g., used paper, glass, plastics), LIBs can neither be directly disposed in landfills nor be simply recycled, as they: (i) contain toxic and flammable materials hazardous to humans and the environment; and (ii) contain critical metals of significant economic value for recovery. The wide spectrum and multicomponent nature of LIB chemistries across the different manufacturers also make it challenging for both manufacturers and governments to build dedicated LIB back collection, sorting, dismantling, and recycling infrastructure to recover the critical metals in a safe and efficient manner. As a result, LIB recycling rates today remain low [4.Editorial Recycle spent batteries.Nat. Energy. 2019; 4: 253Crossref Scopus (28) Google Scholar]. By contrast, the lead acid (Pb-acid) battery industry has set prime examples for sustainable practices and the handling of toxic lead for recovery, achieving more than 99.5% rates of recycling in most parts of the world, compared with <50% collection rates reported for LIBs at bestii. While this disparity can be attributed to the less sophisticated chemistries of Pb-acid, the remarkable achievements in sustainability trace back to the fact that Pb-acid batteries are designed with recycling at their end point [5.Sun Z. et al.Spent lead-acid battery recycling in China – a review and sustainable analyses on mass flow of lead.Waste Manag. 2017; 64: 190-201Crossref PubMed Scopus (114) Google Scholar,6.Tan S.-Y. et al.Developments in electrochemical processes for recycling lead–acid batteries.Curr. Opin. Electrochem. 2019; 16: 83-89Crossref Scopus (30) Google Scholar]. Conversely, manufacturers of LIBs tend to prioritize electrochemical performance and costs, passing the responsibilities of recycling to third-party waste collectors instead. Compared with Pb-acid or other battery chemistries, the supply of critical metals is a unique and urgent problem faced by LIBs. These critical metals include Li, Co, and other transition metals of significant economic value due to both their relative abundance in the Earth’s crust and their disparate geographical availability [7.Tan D.H.S. et al.Enabling sustainable critical materials for battery storage through efficient recycling and improved design: a perspective.MRS Energy Sustain. 2020; 7E27Crossref Google Scholar]. For instance, as shown in Figure 1A , Australia, Chile, and Argentina collectively hold more than 80% of the world’s Li reserves [8.Gil-Alana L.A. Monge M. Lithium: production and estimated consumption. Evidence of persistence.Resour. Policy. 2019; 60: 198-202Crossref Scopus (28) Google Scholar,9.Chen M. et al.Recycling end-of-life electric vehicle lithium-ion batteries.Joule. 2019; 3: 2622-2646Abstract Full Text Full Text PDF Scopus (198) Google Scholar]. Similarly, 59% of the world’s Co supply comes from the Democratic Republic of Congo (Figure 1A) [9.Chen M. et al.Recycling end-of-life electric vehicle lithium-ion batteries.Joule. 2019; 3: 2622-2646Abstract Full Text Full Text PDF Scopus (198) Google Scholar, 10.Shengo M.L. et al.A review of the beneficiation of copper-cobalt-bearing minerals in the Democratic Republic of Congo.J. Sustain. Min. 2019; 18: 226-246Crossref Scopus (24) Google Scholar, 11.Campbell G.A. The cobalt market revisited.Miner. Econ. 2019; 33: 21-28Crossref Scopus (18) Google Scholar]. Such realities place significant material supply risks on critical metals especially for parts of the world without sufficient reserves. While the development of new battery chemistries seeks to replace Co with more abundant Ni and/or Mn, these metals, along with the precious Li, in spent batteries constitute a significant critical material resource, making their recovery from spent LIBs crucial to secure the critical materials within. Moreover, as increasing volumes of critical materials are mined from their original sources and exported as LIBs to other parts of the world, spent LIBs would no longer be seen as waste but instead as a valuable resource for the urban mining of critical metals. Achieving this alleviates critical material supply uncertainties as well as increasing the profitability of battery recycling [1.Li L. et al.The recycling of spent lithium-ion batteries: a review of current processes and technologies.Electrochem. Energy Rev. 2018; 1: 461-482Crossref Scopus (100) Google Scholar]. Figure 1B illustrates the supply chain risks to various critical materials based on today’s LIB growth trajectories. Unsurprisingly, the materials facing the largest supply risks (Co, Li, and Ni) represent those with the lowest relative abundance on Earth. If allowed to continue, rates of critical material consumption will outstrip their global reserves by 2030, highlighting the importance of their recovery and LIB recycling [7.Tan D.H.S. et al.Enabling sustainable critical materials for battery storage through efficient recycling and improved design: a perspective.MRS Energy Sustain. 2020; 7E27Crossref Google Scholar]. Today, the dominant technologies used to recycle LIBs are pyrometallurgy (see Glossary) and hydrometallurgy, which primarily focus on the recovery of expensive Co contained in the cathodes [12.Tan D.H.S. et al.Sustainable design of fully recyclable all solid-state batteries.MRS Energy Sustain. 2020; 7E23Crossref Google Scholar]. However, the economic incentives to expand its adoption in large-scale LIB recycling remains poor due to high costs as well as the limited revenue generated from non-Co materials [1.Li L. et al.The recycling of spent lithium-ion batteries: a review of current processes and technologies.Electrochem. Energy Rev. 2018; 1: 461-482Crossref Scopus (100) Google Scholar,13.Schmuch R. et al.Performance and cost of materials for lithium-based rechargeable automotive batteries.Nat. Energy. 2018; 3: 267-278Crossref Scopus (1268) Google Scholar]. As the EV industry shifts toward low-Co-containing LIBs such as the use of Ni- or Mn-based transition metal oxide cathodes [14.Singer A. et al.Nucleation of dislocations and their dynamics in layered oxide cathode materials during battery charging.Nat. Energy. 2018; 3: 641-647Crossref Scopus (164) Google Scholar,15.Clément R.J. et al.Cation-disordered rocksalt transition metal oxides and oxyfluorides for high energy lithium-ion cathodes.Energy Environ. Sci. 2020; 13: 345-373Crossref Google Scholar], as well as the abundant Fe-based cathodes used by some EV manufacturersiii, the potential prospects of conventional recycling technologies would become less attractive. The primary limitation of conventional pyrometallurgy and hydrometallurgy lies in its methods of material destruction and resynthesis and its high operational costs. As most EOL LIBs retain 80% of their original capacity, it is inefficient to destroy their embedded energy and economic value through thermal or chemical destruction. To this end, direct recycling has been touted as a promising alternative recycling technology to enable critical metal recovery without the breakdown of the LIB’s core components, significantly reducing costs and waste generation while increasing the profitability of LIB recycling (Figure 1C). Direct recycling is found to make the recyclability of low-Co-containing materials, such as Ni, and Mn/Fe-based cathodes profitable (Figure 1C) [12.Tan D.H.S. et al.Sustainable design of fully recyclable all solid-state batteries.MRS Energy Sustain. 2020; 7E23Crossref Google Scholar]. As detailed descriptions on the working methodologies of pyrometallurgy and hydrometallurgy, as well as the processes involved in battery disassembly and electrode separation, are already widely reported in various studies [2.Lv W. et al.A critical review and analysis on the recycling of spent lithium-ion batteries.ACS Sustain. Chem. Eng. 2018; 6: 1504-1521Crossref Scopus (417) Google Scholar,16.Zhang X. et al.Toward sustainable and systematic recycling of spent rechargeable batteries.Chem. Soc. Rev. 2018; 47: 7239-7302Crossref PubMed Google Scholar,17.Huang B. et al.Recycling of lithium-ion batteries: recent advances and perspectives.J. Power Sources. 2018; 399: 274-286Crossref Scopus (310) Google Scholar], they are not discussed in further detail in this review. Instead, direct recycling is a major focus. Direct recycling offers an approach to recover critical metals more efficiently as it avoids the breakdown of spent LIBs, setting the basis for the recovery and regeneration of other components in spent LIBs, such as the Li-containing organic liquid electrolytes and synthetic graphite anodes [7.Tan D.H.S. et al.Enabling sustainable critical materials for battery storage through efficient recycling and improved design: a perspective.MRS Energy Sustain. 2020; 7E27Crossref Google Scholar,18.Grützke M. et al.Extraction of lithium-ion battery electrolytes with liquid and supercritical carbon dioxide and additional solvents.RSC Adv. 2015; 5: 43209-43217Crossref Google Scholar, 19.Liu Y. et al.Supercritical CO2 extraction of organic carbonate-based electrolytes of lithium-ion batteries.RSC Adv. 2014; 4: 54525-54531Crossref Google Scholar, 20.Nowak S. Winter M. The role of sub- and supercritical CO2 as “processing solvent” for the recycling and sample preparation of lithium ion battery electrolytes.Molecules. 2017; 22: 403Crossref Scopus (42) Google Scholar, 21.Yang Y. et al.A process for combination of recycling lithium and regenerating graphite from spent lithium-ion battery.Waste Manag. 2019; 85: 529-537Crossref PubMed Scopus (102) Google Scholar]. However, unlike conventional pyrometallurgy or hydrometallurgy where batteries of different chemistries can be preprocessed together, preprocessing of individual components (while keeping them chemically intact) for direct recycling can be challenging due to a lack of chemical information or safety classification. This potentially increases the costs and sophistication of the sorting and separation of materials from various spent battery chemistries, as each direct recycling process is targeted for specific sets of electrode/electrolyte chemistries. In a typical direct recycling process, pyrolysis or acid treatment is avoided; instead, pretreatment involves spent LIBs being dismantled and their subcomponents, including anode and cathode materials, are exfoliated using either organic solvent dissolution or mild heat treatment to eliminate binders and unwanted organics. The spent cathode materials can be directly regenerated via re-lithiation methods to recover the critical metals within in directly reusable forms. Re-lithiation methods include hydrothermal treatment using aqueous solutions (of LiOH) for low-Ni-containing cathodes or molten eutectic salt (of LiOH and LiNO3) methods for materials with moisture sensitivity [22.Shi Y. et al.Resolving the compositional and structural defects of degraded LiNixCoyMnzO2 particles to directly regenerate high-performance lithium-ion battery cathodes.ACS Energy Lett. 2018; 3: 1683-1692Crossref Scopus (123) Google Scholar, 23.Sloop S. et al.A direct recycling case study from a lithium-ion battery recall.Sustain. Mater. Technol. 2020; 25e00152Google Scholar, 24.Shi Y. et al.Ambient-pressure relithiation of degraded LixNi0.5Co0.2Mn0.3O2 (0 < x < 1) via eutectic solutions for direct regeneration of lithium-ion battery cathodes.Adv. Energy Mater. 2019; 91900454Crossref Scopus (70) Google Scholar, 25.Shi Y. et al.Effective regeneration of LiCoO2 from spent lithium-ion batteries: a direct approach towards high-performance active particles.Green Chem. 2018; 20: 851-862Crossref Google Scholar]. Such re-lithiation methods are commonly followed by thermal annealing with small Li2CO3 or LiOH excess to regain their original structure. While direct regeneration using solid-state sintering especially with low-cost Li2CO3 has been reported [26.Meng X. et al.Recycling of LiNi1/3Co1/3Mn1/3O2 cathode materials from spent lithium-ion batteries using mechanochemical activation and solid-state sintering.Waste Manag. 2019; 84: 54-63Crossref PubMed Scopus (48) Google Scholar,27.Li J. et al.Water-based electrode manufacturing and direct recycling of lithium-ion battery electrodes – a green and sustainable manufacturing system.iScience. 2020; 23101081Abstract Full Text Full Text PDF PubMed Scopus (39) Google Scholar], its shortcomings include the need for an accurate determination of the Li content in spent cathodes, which is challenging to achieve in recycling large batches of spent LIBs from different waste streams. Thus, hydrothermal, molten eutectic salt, or other self-saturating re-lithiation strategies are more effective in direct recycling. However, it should be noted that such direct recycling strategies are relatively new and are mainly developed at the laboratory scale. Enabling its adoption at industrial recycling plants still requires improvements to upstream battery designs that are discussed in subsequent sections. While high collection and recycling rates of other battery types have been mandated in most major economies [28.US Environmental Protection Agency The mercury-containing and rechargeable battery management act – public law 104–142. US Environmental Protection Agency, 1996Google Scholar,29.European Parliament and Council of the EU Directive 2006/66/EC on batteries and accumulators and waste batteries and accumulators. Volume L 266/1. Publications Office of the EU, 2006Google Scholar], LIB recycling mandates are often not stated or kept at conservative benchmarksiv. This is reflective of the current limitations of existing battery recycling technologies, where the cathode is usually recovered while the rest of the cell is typically treated as waste. Depending on the cell chemistry, cathode materials are the largest portion by both cost and mass of any spent LIB (Figure 2A ). However, achieving higher rates of recycling as a function of the entire battery still entails the recovery of other components within the battery. Figure 2A illustrates the cost and mass distribution of various components in a typical LIB. The component costs were calculated based on their mass distribution and unit prices, respectively (obtained from the EverBatt 2020 modelv). It is clear that, to increase rates of recycling beyond 50%, recovery of the anode and electrolytes cannot be ignored. While free of transition metals, graphitic anodes still constitute a significant cost component of LIBs (~15%), making them another important strategic material for recovery. Currently, annual demand for high-quality battery-grade graphite is growing at rates of 10–15%, with its prices reaching as high as US$20 000 depending on its quality, putting it on cost parity with certain critical metals such as Ni [21.Yang Y. et al.A process for combination of recycling lithium and regenerating graphite from spent lithium-ion battery.Waste Manag. 2019; 85: 529-537Crossref PubMed Scopus (102) Google Scholar]. Moreover, spent graphite anodes contain significant amounts of Li deposits (>500 ppm) lost from the cathode and interfacial growth, making recycling of graphite an inevitable outcome for LIBs [30.Rothermel S. et al.Graphite recycling from spent lithium-ion batteries.ChemSusChem. 2016; 9: 3473-3484Crossref PubMed Scopus (101) Google Scholar,31.Markey B. et al.Effective upcycling of graphite anode: healing and doping enabled direct regeneration.J. Electrochem. Soc. 2020; 167160511Crossref Scopus (8) Google Scholar]. Fortunately, compared with cathode materials, graphite is much simpler to handle and recycle, as graphite does not undergo significant structural degradation at its EOL. Figure 2B shows a schematic of a typical graphite recycling process. Spent graphite is first harvested from spent LIBs using physical separation methods similar to those in pyrometallurgy or hydrometallurgy before thermal pretreatment steps to eliminate organic impurities and binders, allowing them to be exfoliated from the current collectors [21.Yang Y. et al.A process for combination of recycling lithium and regenerating graphite from spent lithium-ion battery.Waste Manag. 2019; 85: 529-537Crossref PubMed Scopus (102) Google Scholar]. Subsequently, acid leaching (e.g., with H2SO4) is conducted to extract imbedded Li as well as other metal impurities [32.Gao Y. et al.Graphite recycling from the spent lithium-ion batteries by sulfuric acid curing–leaching combined with high-temperature calcination.ACS Sustain. Chem. Eng. 2020; 8: 9447-9455Crossref Scopus (43) Google Scholar]. The extracted Li is then precipitated using NaOH/Na2CO3 to produce Li2CO3, a precursor for new battery material synthesis. Previous studies have reported Li recovery efficiencies near 100% using such methods [21.Yang Y. et al.A process for combination of recycling lithium and regenerating graphite from spent lithium-ion battery.Waste Manag. 2019; 85: 529-537Crossref PubMed Scopus (102) Google Scholar]. Finally, graphite is regenerated using thermal annealing conducted in a flowing inert gas such as Ar or N2, which has been found to have a performance similar to that of pristine synthetic counterparts. Following the anode, liquid electrolytes are the next-largest component by cost and mass of any spent LIB (Figure 2A). However, unlike benign graphite, they also contain toxic organic solvents and expensive lithium hexafluorophosphate (LiPF6) that are also vital for treatment and recovery. To achieve this, supercritical carbon dioxide (CO2) is employed due to its highly favorable properties for the solvation of various organic materials [18.Grützke M. et al.Extraction of lithium-ion battery electrolytes with liquid and supercritical carbon dioxide and additional solvents.RSC Adv. 2015; 5: 43209-43217Crossref Google Scholar,20.Nowak S. Winter M. The role of sub- and supercritical CO2 as “processing solvent” for the recycling and sample preparation of lithium ion battery electrolytes.Molecules. 2017; 22: 403Crossref Scopus (42) Google Scholar]. In a typical process illustrated in Figure 2C [33.Liu Y. et al.Purification and characterization of reclaimed electrolytes from spent lithium-ion batteries.J. Phys. Chem. C. 2017; 121: 4181-4187Crossref Scopus (39) Google Scholar], spent LIBs are first perforated before allowing liquid electrolyte dissolution and extraction via flowing supercritical CO2. After purification and removal of impurities, the electrolyte is then collected using a cold trap. Unfortunately, electrolyte recycling has yet to be widely adopted among most battery recyclers, largely due to the high capital costs involved in handling CO2 under supercritical conditions (Figure 2D). Additionally, while most CO2-based electrolyte recycling studies reported high yields of electrolyte recovery (~85–90%), significant amount of impurities are still found in the recovered mixtures [18.Grützke M. et al.Extraction of lithium-ion battery electrolytes with liquid and supercritical carbon dioxide and additional solvents.RSC Adv. 2015; 5: 43209-43217Crossref Google Scholar,19.Liu Y. et al.Supercritical CO2 extraction of organic carbonate-based electrolytes of lithium-ion batteries.RSC Adv. 2014; 4: 54525-54531Crossref Google Scholar]. These impurities contain toxic fluorinated compounds or other inorganic impurities caused by solvent decomposition that are undesirable for electrolyte recycling. Future electrolytes should strive for fluorine-free chemistries that are more friendly toward recyclability. However, it should be noted that electrolyte recycling using supercritical CO2 also increases the total amount of energy consumed compared with recycling without electrolytes (Figure 2D). Alternative methods involving solvent extraction and distillation have also been proposed [34.Bankole O.E. Lei L. Silicon exchange effects of glassware on the recovery of LiPF6: alternative route to preparation of Li2Sif6.J. Solid Waste Technol. Manag. 2014; 39: 254-259Crossref Scopus (9) Google Scholar,35.Bankole O.E. et al.Battery recycling technologies: recycling waste lithium ion batteries with the impact on the environment in-view.J. Environ. Ecol. 2013; 4: 14Crossref Google Scholar]. Here, low-cost solvents such alcohols or acetonitrile are used under ambient conditions to extract both the organic electrolytes and Li salts, before being distilled for reuse [18.Grützke M. et al.Extraction of lithium-ion battery electrolytes with liquid and supercritical carbon dioxide and additional solvents.RSC Adv. 2015; 5: 43209-43217Crossref Google Scholar,36.Haas P. et al.Separation of the electrolyte – solvent extraction.in: Kwade A. Diekmann J. Recycling of Lithium-Ion Batteries. Springer, 2018: 155-176Crossref Scopus (2) Google Scholar]. The main benefit of solvent extraction lies with its ability to recover both the organic solvents and Li salts at the same time under close-to-ambient conditions. However, in such cases, the Li salts also undergo decomposition to form HF, POF3, and LiF. Achieving a true closed-loop liquid electrolyte recycling process still requires a redesign of recycling approaches, allowing the separation and precipitation of both organic solvents and Li salts without degradation. Potential solutions need to extend efforts beyond improvements to the recycling process itself and look upstream toward modifying battery chemistries to eliminate fluoride-containing compounds. LIBs today are not designed to be easily recycled, creating disproportionately large obstacles in LIB handling safety, transport, dismantling, and the recovery of critical materials within. Unlike the general waste, metals, and plastics industries, which have extensively coordinated production to recycling practices, with internationally recognized sorting symbols, proper back collection, and processing infrastructures, battery waste recyclers often work independent from their original equipment manufacturers (OEMs). To facilitate LIB recyclability, some potential design changes can be considered. Practically, recycling friendly modifications need to maintain existing LIB performance metrics while allowing ease of material separation and subsequent critical metal recovery. Figure 3A summarizes some potential approaches reported in the literature that can meet both objectives simultaneously. At the electrode level, use of harmful organics during material separation can be reduced if water- or alcohol-soluble binders can be adopted over traditional N-methyl-2-pyrrolidone (NMP) based polyvinylidene fluoride (PVDF) binders [27.Li J. et al.Water-based electrode manufacturing and direct recycling of lithium-ion battery electrodes – a green and sustainable manufacturing system.iScience. 2020; 23101081Abstract Full Text Full Text PDF PubMed Scopus (39) Google Scholar]. To facilitate direct recycling and reduce the occurrence of secondary cathode particle cracking commonly seen in spent batteries, single-crystal-type cathode particles can be adopted instead, which are easier to directly regenerate and exhibit a lower probability of particle cracking [37.Zhong Z. et al.Single-crystal LiNi0.5Co0.2Mn0.3O2: a high thermal and cycling stable cathodes for lithium-ion batteries.J. Mater. Sci. 2019; 55: 2913-2922Crossref Scopus (27) Google Scholar,38.Fan X. et al.Crack-free single-crystalline Ni-rich layered NCM cathode enable superior cycling performance of lithium-ion batteries.Nano Energy. 2020; 70104450Crossref Scopus (160) Google Scholar]. Additionally, single-crystal-type cathodes have been reported to offer higher reversible capacities and more stable cycle performance than conventional polycrystalline cathodes [39.Zhang F. et al.Surface regulation enables high stability of single-crystal lithium-ion cathodes at high voltage.Nat. Commun. 2020; 11: 3050Crossref PubMed Scopus (91) Google Scholar]. To avoid the need to recycle graphite, recent breakthroughs in Li metal anodes or anode-free cell configurations are a highly promising approach to promote ease of recycling while offering increased overall cell energy density at the same time [40.Louli A.J. et al.Exploring the impact of mechanical pressure on the performance of anode-free lithium metal cells.J. Electrochem. Soc. 2019; 166: A1291-A1299Crossref Scopus (96) Google Scholar,41.Weber R. et al.Long cycle life and dendrite-free lithium morphology in anode-free lithium pouch cells enabled by a dual-salt liquid electrolyte.Nat. Energy. 2019; 4: 683-689Crossref Scopus (303) Google Scholar]. Low-cost and environmentally benign carbon-based current collectors have also been reportedly used, which are lower in mass and offer improved stability toward corrosion compared with conventional Cu- or Al-based current collectors [42.Wang C.H. et al.Titanium carbide (MXene) as a current collector for lithium-ion batteries.ACS Omega. 2018; 3: 12489-12494Crossref PubMed Scopus (35) Google Scholar,43.Das P. Wu Z.-S. MXene for energy storage: present status and future perspectives.J. Phys. Energy. 2020; 2032004Crossref Scopus (24) Google Scholar]. At the cell to pack level, packaging and stacking designs can be adapted to facilitate easier dismantling of individual cells by either hand or automation [44.Harper G. et al.Recycling lithium-ion batteries from electric vehicles.Nature. 2019; 575: 75-86Crossref PubMed Scopus (671) Google Scholar]. For example, permanently sealed stainless steel cylindrical battery canisters or pouch-type prismatic cells can be replaced by temporary sealed screw-cap designs or internal vacuum-release valves similar to other consumer products that allow safer disassembly and separation of the active from inactive components [45.Liebmann A. et al.Practical case studies: easy opening for consumer-friendly, peelable packaging.J. Adhes. Sci. Technol. 2012; 26: 2437-2448Crossref Scopus (14) Google Scholar]. Ideally, the dismantling and component separation of high-volume and hazardous LIBs should be conducted using automation, to reduce risks and exposure to workers. However, robotics and its ability to adapt to the wide variety of battery types, form factors, and chemistries is heavily limited [44.Harper G. et al.Recycling lithium-ion batteries from electric vehicles.Nature. 2019; 575: 75-86Crossref PubMed Scopus (671) Google Scholar]. Some degree of standardization in form factors will go a long way to facilitate this. While standardi