Lithium-ion battery
|
An example of a Li-ion battery (used in the Nokia 3310 mobile phone) | |
| Specific energy | (0.36–0.875 MJ/kg) |
|---|---|
| Energy density | (0.90–2.43 MJ/L) |
| Specific power | ~250-~340 W/kg[1] |
| Charge/discharge efficiency | 80–90%[4] |
| Energy/consumer-price | 2.5 W·h/US$[5] |
| Self-discharge rate |
8% at 21 °C 15% at 40 °C 31% at 60 °C (per month)[6] |
| Cycle durability |
400–1200 cycles [7] |
| Nominal cell voltage | NMC 3.6 / 3.85 V, LiFePO4 3.2 V |
A lithium-ion battery or Li-ion battery is a type of rechargeable battery in which lithium ions move from the negative electrode to the positive electrode during discharge and back when charging. Li-ion batteries use an intercalated lithium compound as one electrode material, compared to the metallic lithium used in a non-rechargeable lithium battery. The electrolyte, which allows for ionic movement, and the two electrodes are the constituent components of a lithium-ion battery cell.
Lithium-ion batteries are common in home electronics. They are one of the most popular types of rechargeable batteries for portable electronics, with a high energy density, tiny memory effect[8] and low self-discharge. Beyond consumer electronics, LIBs are also growing in popularity for military, battery electric vehicle and aerospace applications.[9] For example, lithium-ion batteries are becoming a common replacement for the lead–acid batteries that have been used historically for golf carts and utility vehicles. Instead of heavy lead plates and acid electrolyte, the trend is to use lightweight lithium-ion battery packs that can provide the same voltage as lead-acid batteries, so no modification to the vehicle's drive system is required.
Chemistry, performance, cost and safety characteristics vary across LIB types. Handheld electronics mostly use LIBs based on lithium cobalt oxide (LiCoO
2), which offers high energy density, but presents safety risks, especially when damaged. Lithium iron phosphate (LiFePO
4), lithium ion manganese oxide battery (LiMn
2O
4, Li
2MnO
3, or LMO) and lithium nickel manganese cobalt oxide (LiNiMnCoO
2 or NMC) offer lower energy density, but longer lives and inherent safety. Such batteries are widely used for electric tools, medical equipment and other roles. NMC in particular is a leading contender for automotive applications. Lithium nickel cobalt aluminum oxide (LiNiCoAlO
2 or NCA) and lithium titanate (Li
4Ti
5O
12 or LTO) are specialty designs aimed at particular niche roles. The newer lithium–sulfur batteries promise the highest performance-to-weight ratio.
Lithium-ion batteries can be dangerous under some conditions and can pose a safety hazard since they, unlike other rechargeable batteries, contain a flammable electrolyte and are kept pressurized. Because of this, the testing standards for these batteries are more stringent than those for acid-electrolyte batteries, requiring both a broader range of test conditions and additional battery-specific tests.[10][11] This is in response to reported accidents and failures, and there have been battery-related recalls by some companies.
Terminology
Although the word "battery" is a common term to describe an electrochemical storage system, international industry standards differentiate between a "cell" and a "battery".[11][12] A "cell" is a basic electrochemical unit that contains the basic components, such as electrodes, separator, and electrolyte. In the case of lithium-ion cells, this is the single cylindrical, prismatic or pouch unit, that provides an average potential difference at its terminals of 3.7 V for LiCoO
2 and 3.3 V for LiFePO
4. A "battery" or "battery pack" is a collection of cells or cell assemblies which are ready for use, as it contains an appropriate housing, electrical interconnections, and possibly electronics to control and protect the cells from failure.[13][14] In this regard, the simplest "battery" is a single cell with perhaps a small electronic circuit for protection.
In many cases, distinguishing between "cell" and "battery" is not important. However, this should be done when dealing with specific applications, for example, battery electric vehicles,[15] where "battery" may indicate a high voltage system of 400 V, and not a single cell. The term "module" is often used as an intermediate topology, with the understanding that a battery pack is made of modules, and modules are composed of individual cells.[14][15]
History
Before commercial introduction
Lithium batteries were proposed by M Stanley Whittingham, now at Binghamton University, while working for Exxon in the 1970s.[16] Whittingham used titanium(IV) sulfide and lithium metal as the electrodes. However, this rechargeable lithium battery could never be made practical. Titanium disulfide was a poor choice, since it has to be synthesized under completely sealed conditions. This is extremely expensive (~$1000 per kilo for titanium disulfide raw material in 1970s). When exposed to air, titanium disulfide reacts to form hydrogen sulfide compounds, which have an unpleasant odour. For this, and other reasons, Exxon discontinued development of Whittingham's lithium-titanium disulfide battery.[17] Batteries with metallic lithium electrodes presented safety issues, as lithium is a highly reactive element; it burns in normal atmospheric conditions because of the presence of water and oxygen.[18] As a result, research moved to develop batteries where, instead of metallic lithium, only lithium compounds are present, being capable of accepting and releasing lithium ions.
Reversible intercalation in graphite[19][20] and intercalation into cathodic oxides[21][22] was discovered in the 1970s by J. O. Besenhard at TU Munich. Besenhard proposed its application in lithium cells.[23][24] Electrolyte decomposition and solvent co-intercalation into graphite were severe early drawbacks for battery life.
- 1973 – Adam Heller Proposes the lithium thionyl chloride battery, still used in implanted medical devices and in defense systems where greater than a 20-year shelf life, high energy density, or extreme operating temperatures are encountered.[25]
- 1977 – Samar Basu demonstrated electrochemical intercalation of lithium in graphite at the University of Pennsylvania.[26][27] This led to the development of a workable lithium intercalated graphite electrode at Bell Labs (LiC
6)[28] to provide an alternative to the lithium metal electrode battery. - 1979 – Working in separate groups, at Stanford University Ned A. Godshall et al.,[29][30][31][32][33] and the following year in 1980 at Oxford University, England, John Goodenough and Koichi Mizushima, both demonstrated a rechargeable lithium cell with voltage in the 4 V range using lithium cobalt oxide (LiCoO
2) as the positive electrode and lithium metal as the negative electrode.[34][35] This innovation provided the positive electrode material that made lithium batteries commercially possible. LiCoO
2 is a stable positive electrode material which acts as a donor of lithium ions, which means that it can be used with a negative electrode material other than lithium metal. By enabling the use of stable and easy-to-handle negative electrode materials, LiCoO
2 opened a whole new range of possibilities for novel rechargeable battery systems. Godshall et al. further identified in 1979, along with LiCoO2, the similar value of ternary compound lithium-transition metal-oxides such as the spinel LiMn2O4, Li2MnO3, LiMnO2, LiFeO2, LiFe5O8, and LiFe5O4 (and later lithium-copper-oxide and lithium-nickel-oxide cathode materials in 1985)[36][37] - 1980 – Rachid Yazami demonstrated the reversible electrochemical intercalation of lithium in graphite.[38][39] The organic electrolytes available at the time would decompose during charging with a graphite negative electrode, slowing the development of a rechargeable lithium/graphite battery. Yazami used a solid electrolyte to demonstrate that lithium could be reversibly intercalated in graphite through an electrochemical mechanism. (As of 2011, the graphite electrode discovered by Yazami is the most commonly used electrode in commercial lithium ion batteries).
- 1982 – Godshall et al. were awarded the U.S. Patent[40] on the use of LiCoO2 as cathodes in lithium batteries, based on Godshall's Stanford University Ph.D. thesis Dissertation and 1979 publications.
- 1983 – Michael M. Thackeray, John Goodenough, and coworkers further developed manganese spinel as a positive electrode material, after its 1979 identification as such by Godshall et al. in 1979 (above).[41] Spinel showed great promise, given its low-cost, good electronic and lithium ion conductivity, and three-dimensional structure, which gives it good structural stability. Although pure manganese spinel fades with cycling, this can be overcome with chemical modification of the material.[42] As of 2013, manganese spinel was used in commercial cells.[43]
- 1985 – Akira Yoshino assembled a prototype cell using carbonaceous material into which lithium ions could be inserted as one electrode, and lithium cobalt oxide (LiCoO
2), which is stable in air, as the other.[44] By using materials without metallic lithium, safety was dramatically improved. LiCoO
2 enabled industrial-scale production and represents the birth of the current lithium-ion battery. - 1989 – John Goodenough and Arumugam Manthiram of the University of Texas at Austin showed that positive electrodes containing polyanions, e.g., sulfates, produce higher voltages than oxides due to the induction effect of the polyanion.[45]
There were two main trends in the research and development of electrode materials for lithium ion rechargeable batteries. One was the approach from the field of electrochemistry centering on graphite intercalation compounds,[46] and the other was the approach from the field of new nano-carbonaceous materials.[47]
History described above is based on the former stand point. On the other hand, in the recent interview article concerning the first stage of scientific research activity directly related to the LIB developments, it is stated that looking at the major streams in research development,[48] the negative-electrode of today’s lithium ion rechargeable battery has its origins in PAS (polyacenic semiconductive material) discovered by Professor Tokio Yamabe and later Shjzukuni Yata at the beginning of 1980’s.[49][50][51] The seed of this technology, furthermore, was the discovery of conductive polymers by Professor Hideki Shirakawa and his group, and it could also be seen as having started from the polyacetylene lithium ion battery developed by MacDiarmid and Heeger et al.[52]
Commercial production
The performance and capacity of lithium-ion batteries increases as development progresses.
- 1991 – Sony and Asahi Kasei released the first commercial lithium-ion battery.[53]
- 1996 – John Goodenough, Akshaya Padhi and coworkers proposed lithium iron phosphate (LiFePO
4) and other phospho-olivines (lithium metal phosphates with the same structure as mineral olivine) as positive electrode materials.[54] - 2002 – Yet-Ming Chiang and his group at MIT showed a substantial improvement in the performance of lithium batteries by boosting the material's conductivity by doping it[55] with aluminium, niobium and zirconium. The exact mechanism causing the increase became the subject of widespread debate.[56]
- 2004 – Chiang again increased performance by utilizing iron(III) phosphate particles of less than 100 nanometers in diameter. This decreased particle density almost one hundredfold, increased the positive electrode's surface area and improved capacity and performance. Commercialization led to a rapid growth in the market for higher capacity LIBs, as well as a patent infringement battle between Chiang and John Goodenough.[56]
- 2011 – lithium-ion batteries accounted for 66% of all portable secondary (i.e., rechargeable) battery sales in Japan.[57]
- 2012 – John Goodenough, Rachid Yazami and Akira Yoshino received the 2012 IEEE Medal for Environmental and Safety Technologies for developing the lithium ion battery.
- 2014 – commercial batteries from Amprius Corp. reached 650 Wh/L (a 20% increase), using a silicon anode and were delivered to customers.[58] The National Academy of Engineering recognized John Goodenough, Yoshio Nishi, Rachid Yazami and Akira Yoshino for their pioneering efforts in the field.[59]
Price-fixing conspiracy
Information came to light in 2011 regarding a long-term antitrust violating price-fixing conspiracy among the world's major lithium-ion battery manufacturers that kept prices artificially high from 2000 to 2011, according to a class action complaint that was tentatively settled with one of the defendants, Sony, in 2016.[60] The complaint provided evidence that participants included LG, SD, Sanyo, Panasonic, Sony, and Hitachi, and notes that Sanyo and LG had "pled guilty to the criminal price-fixing of Lithium Ion Batteries."[60] p. Sony agreed to settle for $20 million, and also cooperate by, among other things, making employees chosen by plaintiffs available for interviews, depositions and testimony, as well as provide clarifying information regarding the scheme and the documents provided to date, including responding to authentication and clarification questions.[61]Cooperation clause: page 23 - 25.
Construction
