US 2019/0067732 Al  8  Feb.28,2019  [0086]  In some embodiments of the present invention, as  illustrated in FIG.  l(C),  the invented process comprises  continuously feeding an electrically conductive current col› lector  304  (e.g. Cu foil or Al foil) from a feeder roller  (302,  into an active material mixture deposition zone where a wet  active material mixture  308  ( e.g. slurry, suspension, or  polymer gel-like mass) of an electrode active material, a  conductive additive, and a liquid or polymer gel electrolyte  is delivered and deposited onto a surface of the current  collector  308  to form a layer of wet electrode  310  thereon;  basically a coating or casting procedure ( e.g. using a coating  head  306).  [0079]  There are several serious problems associated with  the conventional process and the resulting lithium-ion bat› tery cell or sodium-ion cell:  [0085]  The present invention provides a process for pro› ducing an electrode of an electrochemical cell ( e.g. alkali  metal battery cell) having a high electrode thickness, high  active material mass loading, low overhead weight and  volume, high volumetric capacitance, and high volumetric  energy density. In addition, the manufacturing costs of the  batteries produced by the presently invented process are  significantly lower than those by conventional processes.  [0078]  The prior art lithium battery cell is typically made  by a process that includes the following steps: (a) The first  step includes mixing particles of the anode active material  ( e.g.  Si  nano particles or mesa-carbon micro-beads,  MCMBs), a conductive filler (e.g. graphite flakes), a resin  binder ( e.g. PVDF) in a solvent ( e.g. NMP) to form an anode  slurry. On a separate basis, particles of the cathode active  material (e.g. LFP particles), a conductive filler (e.g. acety› lene black), a resin binder (e.g. PVDF) are mixed and  dispersed in a solvent ( e.g. NMP) to form a cathode slurry.  (b) The second step includes coating the anode slurry onto  one or both primary surfaces of an anode current collector  (e.g. Cu foil), drying the coated layer by vaporizing the  solvent ( e.g. NMP) to form a dried anode electrode coated  on Cu foil. Similarly, the cathode slurry is coated and dried  to form a dried cathode electrode coated on Al foil. Slurry  coating is normally done in a roll-to-roll manner in a real  manufacturing situation; (c) The third step includes lami› nating an anode/Cu foil sheet, a porous separator layer, and  a cathode/Al foil sheet together to form a 3-layer or 5-layer  assembly, which is cut and slit into desired sizes and stacked  to form a rectangular structure (as an example of shape) or  rolled into a cylindrical cell structure. ( d) The rectangular or  cylindrical laminated structure is then encased in an alumi› num-plastic laminated envelope or steel casing. ( e) A liquid  electrolyte is then injected into the laminated structure to  make a lithium battery cell.  [0077]  In other words, there are several conflicting factors  that must be considered concurrently when it comes to the  design and selection of a cathode or anode active material in  terms of material type, size, electrode layer thickness, and  active material mass loading. Thus far, there has been no  effective solution offered by any prior art teaching to these  often conflicting problems. We have solved these challeng› ing issues, which have troubled battery designers and elec› trochemists alike for more than 30 years, by developing a  new process of producing lithium batteries as herein dis› closed.  than 1.2 g/cm 3  even for relatively large particles of  graphite. The cathode active material mass loading of  the electrodes (areal density) is significantly lower than  45 mg/cm 2  for lithium metal oxide-type inorganic  materials and lower than 15 mg/cm 2  for organic or  polymer materials. In addition, there are so many other  non-active materials ( e.g. conductive additive and resin  binder) that add additional weights and volumes to the  electrode without contributing to the cell capacity.  These low areal densities and low volume densities  result in relatively low gravimetric energy density and  low volumetric energy density.  [0084]  In literature, the energy density data reported  based on either the active material weight alone or  the electrode weight cannot directly translate into the  energy densities of a practical battery cell or device.  The "overhead weight" or weights of other device  components (binder, conductive additive, current  collectors, separator, electrolyte, and packaging)  must also be taken into account. The convention  production process results in the weight proportion  of the anode active material (e.g. graphite or carbon)  in a lithium-ion battery being typically from 12% to  17%, and that of the cathode active material ( e.g.  LiMn$_{2}$ 0 4 )  from 20% to 35%.  [0081]  2) With a conventional process, as depicted in  FIG.  l(A),  the actual mass loadings of the electrodes  and the apparent densities for the active materials are  too low to achieve a gravimetric energy density of>200  Wh/kg. In most cases, the anode active material mass  loading of the electrodes (areal density) is significantly  lower than 25 mg/cm $^{2 }$and the apparent volume density  or tap density of the active material is typically less  [0080]  1) It is very difficult to produce an electrode  layer (anode layer or cathode layer) that is thicker than  200 µm (100 µm on each side of a solid current  collector, such as Cu or Al foil). There are several  reasons why this is the case. An electrode of 100 µm  in  thickness typically requires a heating zone of 50-100  meters long in a slurry coating facility, which is too  time consuming, too energy intensive, and not cost› effective. For some electrode active materials, such as  metal oxide particles, it has not been possible to pro› duce an electrode of good structural integrity that is  thicker than 100 µmin  a real manufacturing environ› ment on a continuous basis. The resulting electrodes are  very fragile and brittle. Thicker electrodes have a high  tendency to delaminate and crack.  [0083]  4) Current lithium-ion batteries still suffer from  a relatively low gravimetric energy density and low  volumetric energy density. Commercially available  lithium-ion batteries exhibit a gravimetric energy den› sity of approximately 150-250 Wh/kg and a volumetric  energy density of 450-650  Wh/L.  [0082]  3) The conventional process requires dispersing  dry electrode active materials (anode active material or  cathode active material) in a liquid solvent ( e.g. NMP)  to make a slurry and, upon coating on a current  collector surface, the liquid solvent has to be removed  to dry the electrode layer. Once the anode and cathode  layers, along with a separator layer, are laminated  together and packaged in a housing to make a battery  or supercapacitor cell, one then injects a liquid elec› trolyte into the cell. In actuality, one makes the two  electrodes wet, then makes the electrodes dry, and  finally makes them wet again. Such a wet-dry-wet  process is clearly not a good process at all. 