Unique collector design

Unique fiber collector designs have been attempted to loosen the electrospun scaffold to improve cell infiltration. The principle of the collector design is to reduce the fiber intersections. For example, a half-ball collector containing pillars was designed to achieve cotton ball-like fibrous scaffolds by changing the fiber deposition space (Figure 19.5(a)) [22]. An ethanol bath was used as a collector to obtain low-density electrospun polycaprolactone scaffolds (Figure 19.5(b)) [23]. The ethanol quickly stabilizes the polymer fiber surface to reduce the intersections between fibers. 

A similar effect can be expected for the carbon conductive diluent used in cathode formulations for all commercial cells. In all cases, it is necessary to take into account the particular cell design and the electrical resistivity of the electrode-active mass, perpendicular to the current collector, to optimize cell performance [8], One cannot standardize on any one type of carbon for all battery environments. Fortunately, since carbon is a versatile material, one can find a unique form for each application. 

Generally, redistributors for large-diameter (> 3-ft) columns are of the orifice or weir type. The orifice type is more popular because it does not require the addition of a liquid collector, which consumes vertical space and increases column cost and complexity. Other pros and cons of orifice and weir redistributors, as well as application guidelines for each type of redistributor, are identical to those described earlier for orifice and weir distributors. The general dos and don ts for distributors and for liquid inlets into distributors also extend to redistributors. Additional guidelines unique for selection, design, and operation of redistributors are presented below. 

The optimal design of liquid-junction photovoltaic cells shares constraints with solid-state photovoltaic cells.25 209 Current collectors cast shadows and can reduce the amount of sunlight absorbed in the semiconductor. A constraint unique to the liquid-junction cell is the placement of the counterelectrode relative to the semiconductor-electrolyte interface. Shadows, which reduce efficiency and cause local currents in solid-state photovoltaic cells, may lead to localized corrosion in photoelectrochemical cells. Mass-transfer and kinetic limitations at the counterelectrode and resistance of the electrolyte can play important roles in the optimal design of the liquid-junction photovoltaic cell. These considerations are treated qualitatively by Parkinson.210... 

Figure 8.2 depicts the various components of a commercial cell. Each segment and boundary represents unique considerations for good cell operation. For instance, the boundary of the current collector with the active mass involves the conductivity of the active mass and the current dishibution (collection) within the porous electrode sducture of the active mass. These are intertwined with the electrolyte being common to all components and a key consideration in developing a safe high-performance commercial cell. Safe cell designs alone are not sufficient criteria for a safe commercial cell. The productions operations must not introduce defects that... 

---